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EE 477 Final Report

1. for the GSM and GPIO except for the LCD include p33FJ256GP710 h ifndef SETUP_H define SETUP_H timerl defines setup for tick every 1 2 of a second define T1_OFF Ox7fff Timerl OFF define T1 IDLE CON Oxdfff operate during sleep define T1 GATE OFF Oxffbf Timer Gate time accum off define T1 PS 1 256 Oxffff 1 256 define T1 SYNC EXT OFF Oxfffb Do not synch external clk input define T1 SOURCE INT Oxfffd Internal clock source define SETUP OFF amp T1 IDLE CON amp T1 GATE OFF amp T1 PS 1 256 amp T1 SYNC EXT OFF amp T1 SOURCE INT define T1 PERIOD Oxfda7 define T1 INT OFF Oxfff7 Interrupt Disable define T1 INT PRIOR 3 Oxfffb 011 Interrupt is priority 3 define 1 CONFIG T1 INT OFF amp T1 INT PRIOR 3 define EnableIntT1 asm BSET IECO 3 define DisableIntT1 asm BCLR IECO 3 timer 2 defines setup for 10 bit precision PWM use with OC define T2_OFF Ox7fff Timer2 OFF define T2 IDLE CON Oxdfff operate during sleep define T2 GATE OFF Oxffbf Timer Gate time accum off define T2 PS 1 1 Oxffcf Prescaler 1 1 define T2 32BIT MODE OFF Oxfff7 define T2_SOURCE_INT Oxfffd Internal clock source define T2_SETUP 2 OFF amp T2 IDLE CON amp T2 OFF amp T2 PS 1 1 amp T2 32BIT ODE OFF amp T2 SOURCE INT define T2 PERIOD define T2_INT_OFF Oxfff7 Interrupt Disable define 2 T2 INT OFF define DisableI
2. http ww 1 microchip com downloads en DeviceDoc 70138E pdf 32 Microchip com dsPIC30F Family Overview Online Document unknown publication date accessed February 07 2007 http ww 1 microchip com downloads en DeviceDoc 70043F pdf 33 Microchip com MPLAB C30 C Compiler User s Guide Online Document unknown publication date accessed February 07 2007 http ww 1 microchip com downloads en DeviceDoc C30 Users Guide 51284e pdf 34 Microchip com Section 7 Oscillator Online Document unknown publication date accessed February 07 2007 http ww 1 microchip com downloads en DeviceDoc 70054d pdf 35 Wikipedia org Voice Frequency Online Document unknown publication date accessed January 23 2007 http en wikipedia org wiki Voice frequency 36 Microchip Layout Tips for 12 Bit A D Converter Application Online Document 1999 accessed February 2 2007 http ww1 microchip com downloads en AppNotes 00688b pdf 43 ECE 477 Final Report Fall 2006 37 Meyer Module X PCB Fabrication Process and Layout Basics Online Document 2006 accessed January 23 2007 http cobweb ecn purdue edu dsml ece477 Notes PDF 5 PCB_DESIGN pdf 38 Motorola Motorola Semiconductor Application Note AN1259 Online Document 2005 September accessed January 23 2007 http cobweb ecn purdue edu dsml ece477 Homework Fall2006 AN1259 pdf
3. 0 sets cursor at head of second line LCD put string Up 00 00 00 00 return void LCD put char char ch 5 _TRISD11 ch amp 0b10000000 gt gt 7 _TRISD10 ch amp 0b01000000 gt gt 6 _TRISD9 ch amp 0b00100000 gt gt 5 _TRISD8 ch amp 0b00010000 gt gt 4 _TRISD7 ch amp 0b00001000 gt gt 3 _TRISD6 ch amp 0b00000100 gt gt 2 _TRISD5 ch amp 0b00000010 gt gt 1 _TRISD4 ch amp 0b00000001 _TRISG14 1 RS pin high Clock the cmd in _TRISG13 1 EN pin Clock high for 1 0 1 lt 125 1 _TRISG13 0 EN pin Clock low _TRISG14 0 RS pin low for 1 0 1 lt 125 1 return void LCD_cmd char ch int i All control bits to 0 _TRISG12 0 RW pin Just leave this 0 the whole time _TRISG14 0 RS pin _TRISG13 0 EN pin Command _TRISD11 ch amp 0b10000000 gt gt 7 _TRISD10 ch amp 0b01000000 gt gt 6 _TRISDY ch amp 0b00100000 gt gt 5 _TRISD8 ch amp 0b00010000 gt gt 4 _TRISD7 ch amp 0b00001000 gt gt 3 _TRISD6 ch amp 0b00000100 gt gt 2 _TRISD5 ch amp 0b00000010 gt gt 1 _TRISD4 ch amp 0b00000001 Clock the cmd in _TRISG13 1 EN pin Clock high for 1 0 1 lt 125 1 _TRISG13 0 EN pin Clock low for 1 0 1 lt 125 1 return F 36 ECE 477 Final Report void LCD_reset_time void gl
4. global_hr 0 global_ten_hr if global ten hr 24 global_ten_hr 0 global_day LCD cmd 0xC6 LCD put char global day 48 LCD cmd 0xC8 sets cursor at ten hour place LCD put char global ten hr 48 LCD cmd 0xC9 sets cursor at hour place LCD put char global hr 48 LCD_cmd 0xCB sets cursor at ten minutes place LCD put char global ten min 48 LCD cmd 0xCC sets cursor at minutes place LCD put char global min 48 LCD cmd OxCE sets cursor at ten seconds place LCD put char global ten 48 LCD_cmd OxCF sets cursor at seconds place LCD_put_char global_sec 48 return void LCD put string char string F 38 ECE 477 Final Report Fall 2006 while string Write data to LCD up to null LCD put char string Write character to LCD stringt Increment buffer return end LCD c p33FJ256GP710 h not listed as obtained from Microchip s compiler F 39 ECE 477 Final Report Spring 2006 Appendix G FMECA Worksheet Failure Failure Mode Possible Causes Failure Effects Method of Criticality Remarks No Detection Al Inability to read Software corrupt SD Speech will not Check SD with Medium Medium criticality is write to SD card micro or poor be recorded an external given due to the connection to reader recording of audio headers being the device s main function A2 Micro failure Software
5. After I wrote the software constraints homework and the ethical and environmental analysis homework I began initial software development on the dsPIC30F I learned how the dsPIC s ATD PWM timers and other modules worked and used this to make a proof of concept of the necessary components we would need in the design When the concept was done I began migrating code over to the dsPIC33F I solved problems using Microchip s help with the setup of MPLAB development software and how to initialize the ATD in the 33F I expanded the code to allow more timers run at the fastest rate possible and to be ready for an SD card interface I began testing the SD card interface on the 30F board and after several weeks of testing and debugging I was reading and writing correctly from the SD card I then migrated this over to the 33F This was difficult due to the SPI setup but once the correct ordering of the code was known it was working I then cleaned the SD code and I designed an initial buffering scheme for ATD samples It used a combination of a state machine in the main function several interrupt service routines and flags that when set low or high directed the functionality of the main code When working it was further developed to toggle between the ATD sourcing the PWM and buffering data into the SD card and the SD card outputting data to be sourced on the PWM thus ignoring the ATD When this was working I wrote in where Brad needed to call v
6. s base will be constructed using wood casing and the shade will be purchased A hollow metal cylinder will protrude from the base upwards into the shade and at the end will be a Compact Fluorescent Bulb Taking into account the PCB the major on board components and the lamp apparatus the estimated weight is 8 lbs and the cost is 522 81 7 5 Footprint Layout When considering the DigiSpi s PCB dimensions the first thing the designer must take into account is the three large onboard modules Wi Fi Bluetooth and GSM The size of these modules dictated the initial estimate of the board size to be 6 in x 6 in The dsPIC33FJ256GP710 microcontroller comes 12 mm x 12 mm x 1 mm 100 pin TQFP package there are two packages offered for this model the other being 14 mm x 14 mm x 1 mm 100 pin TQFP the later was chosen due to its smaller size 6 This is roughly centered on the board so that it may easily interface with all the various peripherals The three main modules are located adjacent to each other below the microcontroller The WiPort GSM module and Bluetooth module have very similar footprints as each of these larger components interface with the board through a smaller surface mounted high pitch connector Each module has a manufacturer defined connector that it uses 1 2 4 These small connectors have no influence on the it is instead the footprint of the module itself which influences board dimensions Most
7. 2 8 E 4 5 1 08 0 50 Assumed ground benign condition TQ 10 00 Commercial component TL 1 00 Years in production 2 2 0 5 81 Failures Million Hours 1 72 5 hrs or 19 63 years Table 5 4 LT1528 Linear Regulator 7 MTTF Parameters 17 Fall 2006 ECE 477 Final Report Fall 2006 Overall most of these components seem to have a sufficient MTTF taking into account the scope of the Digi Spi s function less than 10 years with the exception being the LT1121 6 34 years MTTF A regulator with a smaller worst case junction temperature would significantly increase the MTTF and is something that should definitely be looked at in future designs While the other components seem to have sufficient MTTF it is still important to take steps in order to decrease this number because of the fact that the failure rate is constant for a chip s lifespan By properly heat sinking these devices the worst case junction temperature can be greatly reduced This is especially relevant to the MAX9812L LT1528 and LT1121 which have values of 32 0 58 0 and 180 respectively As for the dsPIC33F one possible but small improvement that could be made would be to reconsider its model number to see a part with a smaller number of pins can be found that will still meet our device s needs 5 2 Failure Mode Effects and Criticality Analysis FMECA The functional block breakdown of the Digi Spi schemat
8. 44 ECE 477 Final Report Fall 2006 Appendix A Individual Contributions A 1 Contributions of Brad Sokola I served as the leader for team Digi Spi As part of this I was responsible for communication among the group reviewing and submitting the initial team homework assignments organizing parts acquisition having the TCSP power points edited and ready to go and generally keeping everyone up to date about the project deliverables and due dates This project gave us the chance to experience so many different aspects of the design process This made the leadership role all the more challenging Of primary concern with a project of this magnitude was organization There were numerous deliverables throughout the semester and the timeliness and quality of these deliverables greatly impacts the final product Warren and I purchased and sampled the bulk of the components that went into the final project I kept an updated bill of materials list generated from our final schematic and kept track of the status of all of our parts Initially I was responsible for creating the detailed block diagram including voltage requirements and pin usage In addition to the organizational contributions I was responsible for creating a detailed block diagram including voltage requirements and pin usage This naturally led to me being the point person for the first schematic and later revisions of the schematic I created footprints in OrCad Layout for some of the c
9. 99 00 99 00 Ezurio BISM2 w integrated antenna 1 SparkFun Telit GM862 QUAD PY GSM Module 139 95 1 139 95 Digi Key Linear Technologies LT1121CST 5 PBF ND 5V Regulator 3 25 1 3 25 Digi Key Maxim MAX6817 Switch Debouncer 3 52 2 7 04 Digi Key Maxim MAX9812L Audio Amplifier 0 67 1 0 67 Freescale Digi Key Semiconductor MC145481SDR2CT ND PCM Codec 3 85 1 3 85 Microchip Microchip dsPIC33FJ256GP710 dsPIC Microcontroller 7 66 1 7 66 Digi Key Linear Technologies LT1528CQZPBF ND 3 3V and 3 8V regulators 7 13 2 14 26 Lantronix Lantronix Wiport WiPort WiFi Module 119 00 1 119 00 SparkFun 4UCON PCB SDMMC SD Card Holder 14 95 1 14 95 SparkFun Hitachi GDM1602K 16x 2 LCD 14 95 l 14 95 Total Cost for Major Component 424 58 Table E 1 Major Components 2 52 Digi Key Kemet 399 1259 1 ND 0 1uF 0 12 21 Digi Key Taiyo Yuden 587 1333 1 ND 10uF 0 42 1 0 42 Digi Key Yageo Corp 311 1174 1 ND 0 01uF 0 08 3 025 Panasonic Digi Key ECG PCE4293CT ND 4 7uF 0 27 2 0 54 Digi Key Kemet 399 3318 1 ND 100uF 1 30 1 1 30 Digi Key Rohm 511 1452 1 ND 47uF 0 28 8 226 Digi Key AVX Corp 478 3797 1 ND 100nF 0 39 2 0 77 1 ECE 477 Final Report Fall 2006 Digi Key Kemet 399 1255 1 ND l
10. Fall 2006 ECE 477 Final Report Fall 2006 set up global vars global_curr 0 return void setup_GPIO void set up RA4 and RD2 LED and pushbutton TRISAbits TRISA4 0 LATAbits LATA4 0 PORTAbits RA4 0 Set up push buttons as inputs We don t have to explicitly do this because the TRIS registers default to 1 input in a reset but we will do it anyway as a good programming practice TRISDbits TRISD1 1 TRISDbits TRISD2 1 Set up output to GSM pins TRISBbits TRISB12 0 Set up GSM On Off pin RB12 as an output PORTBbits RB12 1 return void setup timing void setup PLL open timers config timers return void setup periph void void toggleL setup PWM setup ATD Set Up UART UIBRG 2160 9600Baud for 16MIP See FRM Tables Change U2BRG to suit your clock frequency UIMODE 0x8000 Enable 8data no parity 1 stop 015 0x8400 Enable TX Si set SPI port to slowest setting master mode 8 bit Idle state for Clock is high level Primary prescaler 64 1 Secondary prescaler 1 1 must be in this order SPI2BUF 0 SPI2CON1 0x00C0 SPI2CON2 0x0000 5 25 0x8000 enable SPI port void 22 ECE 477 Final Report global_curr global_curr _RA4 global_curr return void set_DutyCycle unsigned int dutycycle taken from heade
11. This contains the definitions and interface necessary for working with the LCD It outputs characters and has a function for updating the runtime of the device from the seconds to the days lude LCD h nternal variables for up time count global_sec global_ten_sec global_min global_ten_min global_hr global_ten_hr global_day LCD_init void ud int b for 1 0 1 lt 10 1 for b 0 b lt 10000 b Wait for the LCD to come up clearing _LATG12 _LATG13 _LATG14 LATD4 0 LATD5 0 LATD6 0 0 0 0 _LATD7 LATD8 LATD9 _LATD10 _LATD11 _TRISG12 _TRISG14 _TRISG13 screen 0 0 0 rf 0 0 0 RW pin Just leave this 0 the whole time 0 RS pin 0 EN pin Write command to data port 0b00111000 LCD cmd 0b 00111000 Sets to 8 bit operation and 2Line 5x8 dot char font Write command to data port 0b00001110 LCD cmd 0b 00001100 Turns on display and cursor off blinking off Write command to data port 0b00000110 LCD cmd 0b LCD cmd C 00000110 Sets cursor mode direction and display shift LCD for i 20 i return 15000 i wait F 35 ECE 477 Final Report Fall 2006 void LCD_reset void LCD reset time LCD cmd 0x80 sets cursor at head of first line LCD put string Stat Rec Off LCD 0
12. port pins SCK1 SDII SDOI and SSI 8 2 2 Serial UART The Serial UART subsystem will be used to communicate with the Bluetooth module and Wi Fi module The Bluetooth module will use port pins UIRX and UITX with a baud rate of 115200 The Wi Fi module will use U2RX and U2TX and communicate using a baud rate of 115200 8 2 3 PWM The PWM subsystem will be used to for the headphone output The first of the available PWM channels will be used on port pin After being output from the PWM the signal will pass through an analog low pass filter before being output to the headphone jack 30 ECE 477 Final Report Fall 2006 8 2 4 Analog to Digital Converter The Analog to Digital Converter will be used to sample the wired microphone This will occur on one of the available analog input pins such as ANO A sampling rate of 8 kHz will be used The dsPIC can provide samples with 10 or 12 bit resolution In this case 10 bit resolution is used and then those samples are shifted down to 8 bits After processing 8 bit samples will be stored to the SD card 8 2 5 Timing module The timing module will be used to generate interrupts to check push buttons and to keep track of system up time The system up time information will be used for outputting to the display 8 2 6 Summary The primary challenges that this design presents are the high maximum current ratings for the wireless communications modules and the variety of interfaces A very durable
13. B 3 ECE 477 Final Report Fall 2006 Appendix C Schematic RD RD6 RDS RD4 gt 2 2 2 1012 36 ND cn cn i 4sPIC33FJ256GP710 SDI2 2 100 Pin IQFP 3202 lt lt PIC lt 1012 36 ND RST A Y V A U2RX U2TX U1TX U1RX 1 4 5 1012 36 ND t SW PUSHBUTTON SPST 2 Micro and Connectors Document Number Team 1 Page 1 Pae Sunday ApHD28 2007 Figure C 1 Microcontroller Block A in FMECA C 1 ECE 477 Final Report Fall 2006 Beurig ANAO Bluetooth GEO C GPIO2 SPI MISO RI O 01uF O 4uF 4 7 uF O 01uF SPITCSB UART DCD SPI UART_DSR GND DTR GPIO4 GND GPIOS Riso gt SPI MOSI GND RXDO tl UART_CTS PCM_CLK PCM IN CP10 4 UART_RTS PCM_SYNC GND UART PCM OUT 22PCM DUT SST IN 8v3 NIC 51 5 GND RXD1 NIC USBIRSV CP4 GPIOB USBIRSV RSV GPIO7 GND GND GPIO8 GND RSV 58 GPIO9 NIC ETH_LED2 LED1 39 2 ETH TX ETH TX 32 4 ETH_RXCEN ETH_TXCEN 34 _ ETH_RX 36 CP1 WLAN_PLED 55 2 o WLAN_ALED PCM SYNC OUT GtB62 QUAD PY GPIOB GPIO4 GPIOS RTS GSM_DTR gt DTR GPIO13 EMMI RX GPIO12 STAT LED GPIO11 RXD GPIO10 EMMI TX DCD DSR GPIOS CTS RING CCIN GPO2 SI
14. BUFF need to update source PWM or SD if src_flag TRUE D src flag FALSI disable IR function in state machine called earlier yes disableATD DisableIntT l curr state UPDATE break case UPDATE go to beginning of card SD setStart if src F 16 ECE 477 Final Report end main c default break Fall 2006 PWM now prime with buffer output func set LCD to show playback from SD card LCD set src P Src pwm MMC buffer output else ATD now set LCD to show listening on ATD LCD_set_sre L src_pwm ATD reset pointers and flags first 1 SD ptr 1 ISR ptr 0 curr state RUN EnableIntTl enableATD break curr state RUN F 17 ECE 477 Final Report setup h setup h Author Karl This code is derived from modules included with the compiler and pasted and used for our setup files is greatly reduced and 2 herein Herb This setups the timers ATD Fall 2006 such as timer h adcl2 h etc Definitions have literally been copied This way 1 the amount of header only what is necessary is contained serial SPI PWM only for debug
15. Considering the condensed timeline of the project the Ezurio was chosen for its superior support and lower power consumption despite its higher cost 3 2 3 Wi Fi Module Selection The project constraints dictate a small discrete form factor that can be hidden in some household or office furniture As a result 802 11b g Ethernet bridges were immediately taken out of consideration Initial research revealed an embedded wireless server from Lantronix that provided 802 11b g connectivity with flexible RS 232 Serial and SPI interfaces as well as 11 GPIO pins 1 Continued research revealed that a Purdue University ECE Senior Design Team in the fall of 2006 investigated a competing product the DPAC Technologies Airborne WLNG Adaptor 12 The DPAC Technologies Airborne though draws more power 575 mA compared to 400 mA lacks a flexible Ethernet port and costs more compared to the Wiport 10 11 Both modules do contain a surplus of GPIO pins that will be unnecessary for the scope of this project The best solution based on cost power constraints and flexibility is clearly provided by Lantronix 3 3 Summary The success of this project relies on seamless and reliable system integration The desire to be very versatile lead to the selection of a microcontroller the dsPIC33F with more memory and processing power than our project would likely need The desire for seamless integration led to the selection of a Bluetooth module with documentatio
16. LCD reset It has been about a second since RB12 was set high to turn on the GSM module so set it low now _RB12 0 GSM_init 0 threshold_setting 1 Set the energy threshold for algorithm Set_Threshold threshold_setting 0 LCD_reset if src_pwm ATD set LCD to show recording from ATD else LCD set src L curr state RUN set LCD to show playback from SD card LCD eet src P buffer_output curr_state RUN enableATD break while sample flag TRU F 15 UM sample flag FALSI if src need to save sample if algorithm 1 have speech most likely copy buffer to SD scope for curr_block 0 curr block lt Te lt ECE 477 Final Report Fall 2006 curr block t for counter 0 counter lt SD_BLOCK_SIZE counter t SD_SetSample counter buffers SD ptr counter SD_ptr SD_ptr 1 NUM_BUFF write sample block SD writeCurr set LCD to show writing block to SD card LCD set src R else SD_ptr SD_ptr 1 NUM_BUFF set LCD to show listening LCD set src L else read in block SD readCurr copy block to main space for counter 0 counter lt SD BLOCK SIZE counter t buffers SD_ptr counter SD GetSample counter SD_ptr SD_ptr 1 NUM
17. LT1528 LT1121 is 3 3 Device Observation Medium Medium criticality damaged short of failure to function measurement of because device loses all peripheral capacitor 3 8 GSM and voltage functionality Bluetooth failure 5 V LCD D2 Vout gt 3 3 V 5 LT1528 LT1121 is Damage to major Observation High High criticality because V or 3 8 V damaged passive components i e excess heat of its potential to cause component failure micro GSM harm to user resistors Wiport Bluetooth LCD D3 Vout does not LT1528 LT1121 is Unpredictable Observation Medium Medium criticality due meet tolerance damaged passive behavior from to potential loss of all values for normal component failure MCU and other device functionality operation resistors powered components Table G 4 Power Management Block D FEMCA
18. SD is used as a file name enum pwmSrc_typ enum pwmSrc_typ src_pwm Algo Variables unsigned char buffer_cnt long int temp_E 0 int temp_Z 0 long int energy long int THRESHOLD int zerocross 0 Sample value with offset subtracted char amplitude 0 0 0 heartbeat and uptime count event happens every 1 2 sec void _ISR _TlInterrupt void unsigned int spi_data clear flags toggle heartbeat TITE 0 1 0 toggleLED timerl_cnt has 1 sec passed if timerl cnt 2 timerl_cnt 0 every second see setup h and inc cnt Check to make sure we aren t doing a threshold setting if threshold setting F 10 ECE 477 Final Report 1 second has passed Update LCD uptime and send to GSM LCD update spi data ReadSPI2 LCD gsm stat spi data 48 return check for event on pushbuttons timing is per setup h void _ISR T4Interrupt void _ 0 TMR4 0 completes a push down push up cycle if so set the appropriate flag based on which push button ef if RD2 1 amp amp RD2 prevRD2 src_flag TRUE if _RD1 1 amp amp _RD1 prevRD1 reset_flag TRUE lt update previous for next use prevRD2 _RD2 prevRD1 _RD1 return ATD conversion complete ISR this also duals as control of the PWM the ATD is not
19. The GM862 GSM Cellular module is encased in a metallic shield Pins protruding from this case will secure the device to the PCB 2 Again drill holes matching the module s footprint are required The WiPort also contained in a metallic shield will mate with the PCB like the GM862 1 9 PCB Layout Design Considerations Microcontroller The extended flexibility of the dsPIC family of microcontrollers allows for simplified board layout and design Utilization of the onboard oscillator eliminates costly external circuitry as well as the complications of these supporting components 6 Attention must still be paid to some basic design rules though First placement of bypass capacitors close to Vaq and Vss pins will insure a stable supply voltage for the processor Next the microcontroller will be oriented to minimize signal traces to the WiPort GM862 GSM Module and Ezurio Bluetooth board Finally attention must be paid to routing noisy signals away from the high impedance ADC inputs to avoid coupling 36 33 ECE 477 Final Report Fall 2006 9 3 PCB Layout Design Considerations Power Supply Due to the impulsive power requirements from transmitting wireless devices an efficient PCB design will needed to maintain stable voltage rails and minimize noise The design of the power supply s traces is very important Intuitively trace widths must be the proper width to handle the necessary current Trace widths for the DigiSpi design
20. amp 0x0007 TEClbits T4IE 4 amp 0 0008 gt gt 3 PWM aka output compare inline void setup PWM void OCICONbits OCM 0 OC1RS 0 Ox03FF OC1CON PWM_SETUP ATD setup adapted from FAQ site on Microchip inline void setup_ATD void D1CON on makes no sense as only converting CHO but o well LCON2bits CSCNA 1 LCON2bits CHPS 0 ADC Clock is derived from Systems Clock with a fast sample time Tad Tcy ADCS 1 1 40M 64 1CON3bits ADRC 0 1CON3bits ADCS 63 setup scanning and _AN29 is only audio input LCON2bits SMPI NUM CHS2SCAN 1 ICSSHbits CSS29 1 LCSSL 0x0000 LPCFGL OxFFFF LPCFGH OxFFFF DIPCFGHbits PCFG29 0 return DD DD UU UU DP gt p og poem ccce op ATD interrupt inline void config_ATD void Clear the A D interrupt flag bit IFSObits AD1IF 0 Enable A D interrupt IECObits AD1IE 0 Turn on the A D converter AD1CON1bits ADON 0 externally visible functions void setup mem void F 21 Scan Input Selections for during Sample bit this must DICON1bits FORM 0 Sample Clock Source GP Timer 3 starts conversion DICON1bits SSRC 2 ADC Sample Control Sampling begins immediately after conversion DICON1bits ASAM 1 10 bit ADC operation lbits AD12B 0 El
21. bad SIP lost Table G 2 Audio and GPIO Block B FEMCA ECE 477 Final Report Spring 2006 Failure Failure Mode Possible Causes Failure Effects Method of Criticality Remarks No Detection Cl No Wi Fi access Software internal User loses ability Observation Low Low criticality because Wiport damage to access trying to log device does not lose bypass capacitor embedded web into the device recording functionality short or pin server connection error C2 No Bluetooth Software internal Failure to record Observation Medium Medium criticality audio streaming BSIM2 damage audio scope PCM because devices loses bypass capacitor output ability to record audio short or pin connection error C3 No GSM access Software internal Inability to call Observation Low Low criticality because GM862 damage into the device user can find other ways bypass capacitor and access live to access audio short or pin audio connection error C4 GSM will not turn Software internal May not beable Observation Low Low criticality because on off or reset damage external BJT to call user can find other ways damage unnecessary to access audio power drain Table G 3 On Board Wireless Peripherals Block C FEMCA ECE 477 Final Report Spring 2006 Failure Failure Mode Possible Causes Failure Effects Method of Criticality Remarks No Detection DI 0 V
22. data The potential misuse of this data is an important ethical concern Environmentally various pollutants and power utilizations are considered The following discusses these concerns and analyzes the ethical and environmental impact of the Digi Spi remote listening device 6 1 Ethical Impact Analysis Since the Digi Spi is a listening device the natural ethical question stemming from this is the use of the recorded voice data This is a current topic seen in the media with the current United States government security measures under question Furthermore the data being recorded can be streamed in real time over the air using a cell phone or computer connection The data is then stored in persistent storage in a well defined format within a portable and scaleable component the SD card This ability to stream and record what was said when can be of positive use Ethically it is important to examine how this utilization can be a negative aspect To solve this ethical issue restricted access and operating environment of the device is essential When the target market of the device under development if it would later be produced is to be a toy or amateur novelty application a liability for clean use does not exist If the device is targeted for professional or military use however the device would need to be more secure Fortunately the device is not targeted for this market and therefore a heightened level of security is not essential
23. diode on the wall wart output in order to limit the supply voltage to an acceptable value In regards to other blocks it is planned to use the web server interface and LCD screen to 18 ECE 477 Final Report Fall 2006 provide feedback to the user on the status of components such as the SD card Bluetooth module GSM module and Wiport 5 3 Summary After analyzing the reliability and safety of the Digi Spi it is clear that component failures and system failures modes must always be on the product developer s mind The parts reviewed in the reliability section while not possibly the most critical considering the inability to perform this analysis on the Digi Spi s larger modules provide a good insight into the expected product lifetime Steps can be made to increase their reliability by properly heat sinking the components thus reducing the temperature factor in each This will have a profound affect on the MAX9812L and the LT1528 As for the FMEC analysis measures can be put in place during the design process to ensure that the most critical failures occur with minimal probability The block of most importance Power Management can be given a better chance to fail safely by placing protection circuitry on the wall wart output therefore reducing the likelihood of device overheating and possible harm to the user 19 ECE 477 Final Report Fall 2006 6 0 Ethical and Environmental Impact Analysis The Digi Spi device is recording voice
24. is the 1 data is being recorded the buffer is left alone but if data is being read from the SD card the buffer is filled before continuing It then enables appropriate interrupts before clearing the reset_flag and setting the current state to a run state The run state and the update state are the two operation modes During the run state the main program loop is polling the sample_flag When that flag is set and the mode is setup to read from the ATD port and write data an algorithm is run to determine if speech is present and if it is the data is written to the SD card The various pointers and interrelation is seen in the diagram after this paragraph and on the left More of the processing is explained through flowcharts in Appendix F Currently the number of buffers is six and the data has the potential to be written every 64 millisecond 512 bytes 0 125 milliseconds per each new one Therefore the SPI operates for SD card I O as fast as possible allowing an I O time of around 10 milliseconds CLK FEFEFE curr_block offset Di curr_block SD ISR_ptr buffer SD SD ptr ISR ptr buffer SD buffers main buffers main buffers 0 buffers n 1 buffers 0 buffers n 1 Figure 10 2 Interrelation of Software and SD card 37 ECE 477 Final Report Fall 2006 If the sample_flag is set and the mode is setup to read from the SD card data is read from the SD card into the buffer
25. methods with the other components Although not all modules were integrated into the final design the design issues related to each module have been left in this section to more clearly show the design process 8 1 Theory of Operation 8 1 1 Power Supply The DigiSpi will be conveniently concealed in a lamp This will allow the device to draw power from a conventional wall outlet 7V DC wallwart will be used Three low drop out linear regulators will be used to produce the 3 3V 3 8V and 5V voltages required for our components 7 Due to impulse currents from wireless transmission the power supply must be able to source significant current For example the data sheet for the GSM module mentions relative current peaks as high as 2A 6 The two LT1528 linear regulators used to supply the 3 3V and 3 8V rails are rated as being able to source up to 3A of current allowing us a sufficient margin above our maximum current requirements 2A for the 3 8V rail and 1A for the 3 3V rail LT1121 used for the 5V rail is rated as being able to source 150mA 23 This is sufficient to power the LCD which requires only 120mA 12 The Microcontroller and Wi Fi Server will be powered by the 3 3V rail The GSM module and Bluetooth module will be powered by the 3 8V rail The LCD will be powered off of the 5V rail 8 1 2 Microcontroller The microcontroller that will be used is the dsPIC33FJ256GP710 6 It will be powered from the 3 3V supply rail and will
26. of secure software If this device were to be designed for use in a professional setting the choice of programming language or the construction of the software should be reconsidered with an eye towards security Therefore in addition to the warning labels and user manual outlined above the device has been designed to fit into a common household item and function off of a wall wart In addition if the product was to be marketed the system would be sealed and unable to be opened outside of removing the SD card This way the PCB could not be removed and used in a different application To prevent this issue the user manual will state that the developers are not responsible when the PCB is used in a different application than what it was designed for Finally the ethical issues of electricity power and electrical signals need to be considered The PCB is enclosed in a common household device such as a lamp to protect it from the elements As stated above if the device would be manufactured it would be sealed This not only deters reuse but keeps the device clean and reduces a risk of electrical injury The worst issue is electro magnetic fields EMF from the GSM and WiPort In fact an EE Times article states that pulsed electromagnetic energy generated by electronic devices causes stress to the human body 26 The EMF generated is part of the WiPort and GSM module and therefore their operation is kept within there limits To aid with t
27. off board peripherals the audio and general purpose I O the on board wireless modules and the power supply The power supply block is most critical to the design because it has the highest potential for causing harm to the user or irreparable damage to other components 51 Reliability Analysis An important part of any design process is a thorough reliability analysis where the potential weak points of the circuit are analyzed and their failure rates are estimated Aside from its wireless modules the Digi Spi consists of number of components worth consideration these include the dsPIC33F microcontroller LT1528 LDO voltage regulator LT1121 LDO voltage regulator and MAX9812L microphone pre amplifier These components were chosen because aside from the wireless modules which do not lend themselves to such an analysis they make up the primary non passive elements in the circuit The Military Handbook for Probability Prediction of Electronic Equipment 21 was used to calculate the failure rate Ap and mean time to failure MTTF for each component All equations and parameter values were chosen based on the guidelines outlined in this document The four parts to be analyzed all fall under the MIL HDBK 217F microcircuit model The following equation defines this model 4 C 7 z 7 Ciis the microcircuit die 15 ECE 477 Final Report Fall 2006 complexity failure rate is the temperature factor is the pack
28. operate at a core frequency of 120 MHz and an instruction frequency of 33 MHz The choice of operating frequency is made such that the micro is able to run multiple timer modules and have ample time to perform all of its primary functions including sampling and analyzing audio The processing frequency is I O bound based upon the rate of writing to the SD card In the final project this needs to be as fast as possible This means a timing to write 512 blocks of data is about 10 milliseconds The ATD sampling has a frequency of around 60 milliseconds for 512 samples Therefore the operating frequency is at 28 ECE 477 Final Report Fall 2006 least five times faster than it needs to be This is warranted in this design in case other functionality needs to be implemented aka version 2 Since the device will be plugged into the wall lowering the operating frequency to conserve power is not necessary The microcontroller will be responsible for accepting audio input push button inputs writing to and reading from the SD card interfacing with the Wi Fi and GSM modules outputting audio to the headphone jack as well as performing filtering operations on the sampled audio 8 1 3 LCD The LCD will provide users with recording information such as the current up time and the amount of speech recorded so far This feature is especially useful for users who want a quick way to confirm that the device is functioning A user could start speaking an
29. possibility of snapping a connector off the board while trying to plug cable The through holes on the footprint for our audio connectors were a bit tight We were able to still mount the connectors however a little more room would make the fit much better Two of our footprints PCM Codec and Bluetooth module had the pin out reversed leading to some bending of pins and fly wiring These footprints also would be changed Knowing now what we have decided to go with in terms of a speech detection algorithm our microprocessor choice is really overkill for this type of design A cheaper micro with less memory and fewer pins could be utilized for this project Finally given additional time support for the FAT file system would be included in the micro so that the files could be read from any SD card reader instead of using the Digi Spi SD card companion device These are the most obvious and useful changes to make However that does not mean that they are the only ones A likely inclusion in a second generation would be a custom built Bluetooth microphone to be included with the Digi Spi device Unfortunately most available Bluetooth microphones are designed with less sensitive microphones This application requires a more sensitive microphone to pick up conversations within a reasonable area of the microphone 39 ECE 477 Final Report Fall 2006 12 0 Summary and Conclusions This course certainly utilizes a variety of skills As a group
30. status 0 return SD_ERR find the start of the read do status SPIRead F 28 ECE 477 Final Report while status START BLOCK TOKEN read the bytes theData buffer for offset 0 offset lt SD BLOCK SIZE offset t theData SPIRead theDatatt SD_Disable pump for eight cycles according to spec SPIWrite OxFF return OK write a block of 512 bytes SD_BLOCK_SIZE to the SD card unsigned char SDWriteBlock unsigned long block buffer_typ theData unsigned int i unsigned char status unsigned char res 1 while res res InitSD setup the write command and block unsigned char CMD24 WRITE SINGLE BLOCK 124 0 00 0 00 0 00 0 00 0 block block SD BLOCK SIZE need to be correct offset CMD24 WRITE SINGLE BLOCK 1 block amp OxFF000000 gt gt 24 CMD24 WRITE SINGLE BLOCK 2 block amp OxOOFF0000 gt gt 16 CMD24 WRITE SINGLE BLOCK 3 block amp 0 0000 00 gt gt 8 CMD24 WRITE SINGLE BLOCK 4 block amp 0x000000FF SD Enable Send the write command status SD WriteCommand CMD24 WRITE SINGLE BLOCK if status 0 return 1 write data start token SPIWrite OxFE write all the bytes in the block theData buffer for i 0 i lt SD_BLOCK_SIZE i SPIWrit
31. the software creates a tractable and scaleable design This successfully fulfills the necessary timing criteria observed herein and enables a compact design for efficiency 38 ECE 477 Final Report Fall 2006 11 0 Version 2 Changes After spending the semester learning about and designing our project there are a number of changes that would be made to version 2 This would include changes to our schematic custom footprints layout component selection and software implementation First a few changes would be made to the schematic to improve audio quality We would purchase a more sensitive microphone and look into possibly doing some sort of automatic gain control Also a volume control would be added for the line level output even though this is designed primarily for debugging Changes would also be made to the GSM microphone input circuitry The signal for the GSM microphone input could be taken after the input LPF rather than from the PWM output This would likely improve audio quality The PCB as a whole should also be better shielded from the GSM antenna to prevent interference Second there were a few layout and footprint errors that we would change to make construction easier The two audio jack connectors were located near but not quite on the edge of the board In a second revision these connectors should be moved so that they sit flush on the edge of the board to make connecting microphones and headphones easier and removing any
32. 012345678910 X1 TOTAL ECE 477 Final Report TABLE OF CONTENTS Abstract 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 11 0 12 0 13 0 Project Overview and Block Diagram Team Success Criteria and Fulfillment Constraint Analysis and Component Selection Patent Liability Analysis Reliability and Safety Analysis Ethical and Environmental Impact Analysis Packaging Design Considerations Schematic Design Considerations PCB Layout Design Considerations Software Design Considerations Version 2 Changes Summary and Conclusions References Appendix A Individual Contributions Appendix B Packaging Appendix C Schematic Appendix D PCB Layout Top and Bottom Copper Appendix E Parts List Spreadsheet Appendix F Software Listing Appendix G FMECA Worksheet iii Fall 2006 gt ECE 477 Final Report Fall 2006 Abstract This report details the semester long development of the Digi Spi intelligent listening device The device is an audio surveillance system that is housed discreetly inside of a lamp The device edits out non speech audio and allows the user to save this audio to an SD card and play the audio back for listening using a headphone jack The device can be accessed to playback live audio via a cellular phone module Recorded audio from an SD card can be accessed by listening to playback from the headphone jack The desire to create a simple surveillance device incorporating audio processing
33. CD put string Threshold return F 13 ECE 477 Final Report Fall 2006 RUNTIME ENABLE inline void start void run_timers run periph return fills up the buffer at the start of the transition to MMC output inline void buffer_output void int buffer_num 0 int samp_num 0 prints READ MSG for buffer num 0 buffer num lt NUM BUFF buffer SD readCurr for samp num 0 samp num lt SD BLOCK SIZE samp_num buffers buffer_num samp_num SD_GetSample samp_num return check for the energy being above the threshold unsigned char algorithm void if temp E gt THRESHOLD 150 return 1 return 0 MAIN FUNCTION x int main void int curr block 0 int counter 0 int GSM_init 1 force start reset_flag TRUE main loop is a giant state machine while 1 if reset flag TRU Pu curr state RESET reset flag FALSE switch curr_state F 14 ECE 477 Final Report case RESET else case RUN setup start Fall 2006 Only toggle the On Off pin on the GSM if this is a hardware reset if GSM init if GSM_init RB12 1 Set On Off pin high for 1 sec threshold_setting 1 Set Threshold Set the energy threshold for algo threshold setting 0
34. CSpytek UHF transmitter receiver The MSCSpytek UHF transmitter receiver as seen in Figure 2 is a two component wireless surveillance system The compact transmitter and receiver are designed with modest external interfaces This is indicative of the product s simplified operating mode The transmitter features an antenna for sound transmission and an on off switch The receiver features an antenna on off switch and a jack for listening to the received audio The transmitter is powered by a lithium ion battery which can sustain up to five days of continuous use and the receiver employs a PP3 battery for up to 4 days of continuous use 30 Figure 7 2 The positives of this product s packaging design are that both of these components are relatively compact and the simplified designs allow for ease of operation However much like the Spytronix device the transmitter does little to conceal its actual function if found The battery life of this device is much improved over the previously compared product but it still remains a limiting factor Also another negative is that there is no digital storage therefore this must either be setup external to the receiver or the user must be listening at all times The most important feature the DigiSpi takes from this device is its wireless capability The function of the on board GSM module which allows for live listening is very similar to the UHF system and it in fact has an even greater
35. ECE 477 Final Report Spring 2007 Team Code Name Digi Spi Team ID 1 Team Members 1 is Team Leader 1 _Brad Sokola Signature Date 2 _Karl Herb Signature Date 3 _Warren Santner Signature Date 4 Justin Lanning Signature Date Comments ECE 477 Final Report Fall 2006 REPORT EVALUATION Component Criterion Score Multiplier Points Abstract 0123456789 10 Project Overview and Block Diagram 012345678910 X2 Team Success Criteria Fulfillment 012345678910 X2 Constraint Analysis Component Selection 012345678910 X2 Patent Liability Analysis 012345678910 X2 Reliability and Safety Analysis 012345678910 X2 Ethical Environmental Impact Analysis 012345678910 X2 Packaging Design Considerations 012345678910 X2 Schematic Design Considerations 012345678910 X2 PCB Layout Design Considerations 012345678910 X2 Software Design Considerations 012345678910 X2 Version 2 Changes 012345678910 X1 Summary and Conclusions 012345678910 X1 References 012345678910 X2 Appendix A Individual Contributions 012345678910 X4 Appendix B Packaging 012345678910 X2 Appendix C Schematic 012345678910 X2 Appendix D Top amp Bottom Copper 012345678910 X2 Appendix E Parts List Spreadsheet 012345678910 X2 Appendix F Software Listing 012345678910 X2 Appendix G FMECA Worksheet 012345678910 X2 Technical Writing Style 012345678910 X8 CD of Project Website
36. Fall 2006 ECE 477 Final Report Fall 2006 Software Files main c Ki main c Author Karl Herb Contributors Justin Lanning Brad Sokola Warren Santner Core software file for project Designed for a dsPIC33FJ25GP710 and for building to assembly and binary with Microchip s MPLAB C30 compiler This code contains inline functions for setting up the microcontroller and times all of the devices according to timing outlined in setup c main c pulls in setup h to gain access to the setup configurations The code contains a main polling loop and is a hybrid model with interrupt service routines for timer 1 timer 4 and the completion of an ATD conversion Header files finclude p33FJ256GP710 h include setup h include SD h include LCD h configuration register setup these must be defined here and must use the macros found in p33FJ h this makes the device have an IF of 33 3MHz and clock of 66 6MHz xf _FBS RBS_NO_RAM amp BSS NO FLASH amp BWRP_WRPROTECT_OFF _FSS RSS_NO_RAM amp SSS NO FLASH amp SWRP WRPROTECT OFF ry _FGS GSS_OFF amp GCP_OFF amp GWRP_OFF Jus _ FRCPLL amp IESO OFF amp TEMP OFF _FOSC FCKSM_CSDCMD amp OSCIOFNC ON amp POSCMD NONE 13 _FWDT FWDTEN OFF amp WINDIS OFF amp WDTPRE PR32 amp WDTPOST 51 Er _FPOR FPWRT_PWR1 setting the size of the sample buffers def
37. GE Unkown Compact Fluorescent Light bulb 5 90 1 5 9 Wal Mart Unknown Unkown Lamp shade 7 99 1 7 99 Radio Shack Radio Shack 42 2497 12 Inch Shielded Stereo Audio Cable 4 99 2 9 98 Target Unknown Unkown Extension Cord 2 99 1 2 99 Radio Shack Radio Shack 273 1696 Wall wart 29 99 1 29 99 571 Mouser Tyco Electronics AMP 1042574 5 pin connectors for LCD LCD headers 0 29 2 0 58 571 5 Mouser Tyco Electronics AMP 103957 1 2 pin connector for LCD 0 38 1 0 38 571 6 pin connectors for SD card LCD LCD Mouser Tyco Electronics AMP 1042575 headers 0 34 4 1 36 571 Mouser Tyco Electronics AMP 1042573 4 pin connectors for Push Buttons 0 29 2 0 58 Wire for the connectors was acquired from the Senior Design Lab Total Cost of Miscellaneous Components 77 99 Total Cost of Project 522 81 Table E 3 Miscellaneous Components E 3 ECE 477 Final Report Fall 2006 Appendix F Software Listing Code organization Item at the head of the arrow has control over the functions and data at the tail The organization is the name in the gray box the global variables and then the functions either declared and or defined in that file main c int ISR_ptr int SD int cnt uchar buffers NUM_BUFF SD BLOCK SIZE int first int Omer cnt int prevRD2 int prevRD1 src flaq sample flag reset flag flag src pwm curr set ulong buffer cnt long temp E inttemp Z long energy long THRESHOLD int zerocross char test
38. If the device was to be made more secure it would ideally have a single phone number have a lock on the SD card have its wireless network uniquely encrypted and have a digital lock on the control panel Hence in order to avoid this potential issue of using a non secure and amateur device in a secure or professional area a warning label must be placed on the device saying it is not intended for any professional or military use but solely as a novelty This would also be stated in the user manual In addition the manufacturer and even the developers of the device are held responsible when the component is used in a negative manner Therefore in the user manual there will be a statement claiming that the developers are not reliable for any harm brought upon someone through an unethical use of the device This would even include reusing the data on a computer to manipulate it or hold it against a person 20 ECE 477 Final Report Fall 2006 Adding to the military and professional use discussion the device is not designed for rigorous use Ethically a device used in a professional environment needs to be fail safe and highly portable to operate under a variety of environmental conditions In addition its software design needs to be secure scaleable and safe from tampering A Military Embedded Articles states that the C language is not favorable for the development of secure applications 25 Other software languages allow for easier designing
39. MCLK RESET SIMRST 01 BC847BL 02 PWRCTL SIMIO MIC_HF 5 C1013 TXD AXE MIC_MT WC Mia EAR_MT EAR MT Charge GND GND GND Peripherals Document Number Rev Team 1 2 3 5 Date Sunday April 29 2007 Sheet 1 of 1 Figure C 2 Peripherals Block C in FMECA C 2 ECE 477 Final Report Fall 2006 C23 10uF 0 1uF c42 2 1000uF R2 330 LT1528 LT1528 LT1121 5 A itle Power Document Number Rev Team 1 Page 3 24 Sunday April 22 2007 Sheet Figure C 3 Power Block D in FMECA C 3 ECE 477 Final Report Fall 2006 3 2 6 1 O 1uF PHONEJACK PushButton_Input_Header 5 J8 R11 2 4 3 3V N 2 3 PHONEJACK PushButton Input Header H 1 ret VAG RO Ti 3 PI Tl 5 TG B 7 vdd vss 8 FSR FST g DR DT 10 BCLKR BCLKT PDI MCLK MC145481 Tying the Mu A pin to Vss selects A Law encoding Document Number Team 1 4 Sunday April 29 2007 Figure 4 Audio GPIO Block FMECA ECE 477 Final Report Fall 2006 Appendix D PCB Layout Top and Bottom Copper 01001010101 ECE 477 1 Figure D 1 PCB top copper ECE 477 Final Report Fall 2006 eje meo CJooOO 00O Figure D 2 PCB bottom copper D 2 ECE 477 Final Report TekGear Appendix E Parts List Spreadsheet Fall 2006 Bluetooth Module
40. SE GSM Module ER 3 8V DC Headphone MIC jack Figure 1 2 Block Diagram Figure 2 above shows a block diagram of the final system including the pin usage interfaces relevant supply voltages and regulator requirements The decisions necessary to realize the successful development of this device will be considered in the following sections Note that when PWM is mentioned in the following sections it refers to the pin OCI ECE 477 Final Report Fall 2006 2 0 Team Success Criteria and Fulfillment 1 An ability to record an audio signal The Digi Spi device successfully samples audio from an A to D port This is demonstrated by outputting the audio sample with the PWM 2 An ability to modify or filter an audio signal The Digi Spi device contains an algorithm using threshold detection to determine if speech is present and displays if the device is Listening or Recording based upon the signal relation to the threshold Ifthe threshold is exceeded it is recorded to the SD card This is demonstrated by the playback of one s voice in which the pauses during their speech are removed 3 An ability to display and modify current settings via the LCD and push buttons The LCD is able to display the current recording status recording listening or playback the current status of the cellular module the current microphone being used and the up time of the device The user can change the device from recordi
41. TRISC4 define SDI PORTFbits RF7 define SDI DIR TRISFbits TRISF7 define SCK PORTFbits RF6 define SCK DIR TRISFbits TRISF6 define SDO PORTFbits RF8 define SDO DIR TRISFbits TRISF8 define SD Enable SD CS 0 define SD Disable SD CS 1 internal types and definitions typedef unsigned char buffer_typ F 26 ECE 477 Final Report local buffer for the current sample buffer typ buffer SD BLOCK SIZE global pointers for blocks unsigned long block unsigned long total blocks legacy flag unsigned char synced internal function declarations unsigned char SDReadBlock unsigned long unsigned char SDWriteBlock unsigned long void InitSPI void unsigned char InitSD void unsigned char SD WriteCommand unsigned char cmd unsigned char SPIRead void void SPIWrite unsigned char data functions definitions unsigned char setup SDSPI void unsigned char res 0 unsigned long start block InitSPI res InitSD do while res res InitSD res SDReadBlock start block while res internal for block pointing to at the time set to 1 as future implementations may have block 0 contain information metadata about the samples curr_block 1 synced 0 return OK reset the SD card to beginning see above why it is set to 1 void SD_setStart void curr block 1 return obtain the sample in th
42. age failure rate is the environmental factor is the quality factor and is the learning factor measure of chip manufacturing maturity For each of the four components and are all the same value due to a number of universal assumptions The first of these being that the Digi Spi is assumed to be operating in a temperature and humidity controlled environment with a fixed ground Table 3 2 of the MIL HDBK 217F defines these conditions to be ground benign giving all components a value of 0 5 MIL HDBK 217F Section 5 10 The second assumption is that the Digi Spi will have the quality of a commercial product giving them a value of 10 00 MIL HDBK 217F Section 5 10 The final assumption is that all of these components have been in production over two years giving them a m value of 1 00 MIL HDBK 217F Section 5 10 Having stated these universal assumptions the only variables left to consider are and C2 The following set of tables outlines the Ap and MTTF calculation for each selected component All justifications for the and values are from the component data sheets unless they are expressly assumed Parameter Value Justification 0 56 16 bit with 40 bit extended precision Assumed 32 bit MOS microprocessor TT 0 95 Digital MOS T 85 degrees C C5 0 13 100 pin TQFP eq 3 was used 3 0 E 5 100 1 82 TE 0 50 Assumed ground be
43. and high current wallwart along with regulators that have high current ratings will be necessary to accommodate the short high power bursts With the device adhering to the outlined hardware design constraints a durable and discreet embedded device is the result 31 ECE 477 Final Report Fall 2006 9 0 PCB Layout Design Considerations A functional PCB layout will be critical to accommodate the plethora of necessary components in a discrete form factor Mechanical concerns for board to board connections noise management to maximize audio signal integrity and stable power distribution throughout the PCB will all be carefully analyzed 91 Layout Design Considerations Overall To enable the extreme flexibility of the DigiSpi surveillance device many components will have to be seamlessly integrated Wise component layout will be important to manage EMI The following strategy will be used in part placement digital analog and mixed signal devices will be separated to reduce noise and interference 36 If possible high frequency parts will be segregated from devices that operate at a clock speed lower than 40 MHz 36 In the DigiSpi PCB layout the power supply electronics will be isolated in a separate quadrant of the PCB The dsPIC and GM862 GSM Cellular modem will both be handling analog audio so they will be placed near each other in the mixed signal section of the board The dsPIC will also be located on the analog power and g
44. arious LCD functions and where Justin needed to do signal processing I handed the code off to them and they put the finishes touches on it and removed several bugs The 30F experimentation with the SD card led to the development of a Python program and intercommunication protocol over the SCI port between the Python and the microcontroller This was in the hopes of making an au file from the data on the SD card for future playback ECE 477 Final Report Fall 2006 The data was correctly obtained from the SD card but the au file was unable to produce a decent playback Despite a circuit being built to interface the SD card SCI port and the dsPIC30F and a software program compiled to communicate with it this design was abandoned in the end I was not able to have it work at a level suitable to present as an integration of the component Upon conclusion of the project I developed the poster documented all of the software with diagrams listings and revisions to the initial homework and finalized the website for archiving A 3 Contributions of Warren Santner The successful completion of our project was certainly a team effort but we all focused our areas of expertise on certain aspects of the design My two core responsibilities were the PCB board layout and packaging For the PCB layout I rendered a large number of footprints with the help of Brad Sokola and Justin Lanning The board placement and routing was entirely my responsibi
45. ay of infringing on just writing data to an SD card In order to assess the potential patent infringement of the speech detection algorithm specifics about how the Digi Spi speech algorithm functions must be known The speech detection algorithm consists of a simple threshold comparison A threshold is set based on the average level over roughly a second when the device is turned on An offset is added to that threshold to prevent random variation in noise levels from triggering the device to record Finally blocks of audio samples are compared to the threshold and a determination is made 4 1 Results of Patent and Product Search A number of recording devices advertising voice activated modes were found Two representative commercial devices are included in the following sections Many patents involving speech detection were found An analysis of the three most similar to Digi Spi device has been included Patents were found using Google Patent Search with terms speech detection and voice activity detection 4 1 1 33 Hour Mini Digital Recorder 13 This device is a small recording device that features a voice activated record mode According to the product description the easy to use Voice Activated Mode will only begin 10 ECE 477 Final Report Fall 2006 recording when a sound is heard and it will stop recording after a few seconds where no sounds are present 13 It is difficult to tell how the Spytronix device a
46. batteries with a battery life of approximately 12 hrs 13 The compact design of this device makes it very portable and concealable and the external interface is quite IX COM simple since it only involves one push button and a small LCD display However one obvious negative of this product s design is 445 that it will not be confused for anything other than a digital recorder thus if found by the person being spied on they would immediately Figure 7 1 know the situation Also its single push button design allows for only limited recording options as there is no other way to interface with the device i e wirelessly The final negative is that the product s recording time is significantly limited by its battery constraints Our product packaging is similar to the Spytronix device in that it will include a small external LCD to view the current recording status and also in our minimal use of push buttons only 2 Due to a number of large on board wireless modules Wi Fi Bluetooth and GSM our packaging needs to be a little larger and also the use of AC power is desired Taking into account these two factors it has been decided to conceal the device in a custom lamp due to its 24 ECE 477 Final Report Fall 2006 ability to mask the device s true functionality This is an improvement over the Spytronix recorder because it allows for long uninterrupted surveillance and effectively hides the product s true intention 7 3 MS
47. buffering its conversion is ignored void _ISR _ADClInterrupt void int sample if src_pwm ATD output the sample and make the 10bit sample into an 8bit sample to gain maximal use of the SD space set DutyCycle 0 buffers ISR_ptr cnt ADCIBUFO gt gt 2 sample buffers ISR_ptr cnt adjust the amplitude for the processing algorithm on each sample and total the energy approrpiately if sample gt ZERO_LEV amplitude sample ZERO_LEV else N amplitude ERO LEV sample energy amplitude and if Fall 2006 ECE 477 Final Report else output the value in the current buffer position to the PWM for audio output remembering to make the 8bit back into 10bit for near consistency unsigned char theSamp buffers ISR_ptr cnt set_DutyCycle theSamp lt lt 2 adjust pointers and look for events if cnt SD BLOCK SIZI Gl adjust count and if necessary ISR ptr and request for more data data output if need be cnt 0 ISR ptr ISR ptr 1 NUM BUFF if first 1 prep SD ptr first 0 SD ptr 0 flag the event and setup for the signal processing algo if need be sample_flag TRUE if src_pwm buffer temp_E energy temp Z energy 0 zerocross 0 _ 0
48. ctually determines voiced sound from unvoiced sounds It appears most likely that this would be implemented with a simple fixed threshold to determine if voice is present There is no indication of a patent associated with this device on the website cited 4 1 2 Coby CX R55 Voice activated cassette recorder 14 This is a small battery powered cassette recorder that features a Voice Activated system with Adjustable Sensitivity control 14 It features a built in microphone as well as a jack for an external one The adjustable sensitivity control appears to change the threshold that the voice activated system uses Once again there is little indication of how the device actually decides if audio is voiced or not This device likely also just uses a threshold comparison However in this case the threshold can be changed via the adjustable sensitivity control 41 3 VAD CNG software 15 This product is a software package that producers of VoIP phone systems could include in their product A number of VoIP phones such as the Cisco SPA901 16 were found that mentioned voice activity detection as one of the voice features Unfortunately none of the products found had a description of what the voice activity detection consisted of This lead to the determination that a software package marketed towards VoIP phone manufacturers would perhaps be a better product to look at in terms of analyzing the actual functioning of the detection Althoug
49. d observe the change in the amount of speech recorded to confirm that the device is functioning It is also a useful way to tell if the SD card needs to be replaced in order to continue recording The LCD used in this application will be the Xiamen Ocular GDM1602K 12 It will communicate with the microcontroller via a parallel connection According to the LCD data sheet it can run off of a supply voltage of 5V The LCD will be powered by the SV rail 8 1 4 WiPort Wi Fi Server The WiPort will provide wireless access for users to connect to This is an important function since it will allow users within range to connect and change recording settings such as threshold levels and monitor recording status It requires a 3 135V to 3 45V supply 1 so it will be supplied by the 3 3V rail It will communicate with the Microcontroller via an SPI connection that will be shared with the GSM module 8 1 5 GSM Module The GSM module will provide a means of world wide call in access to hear what is happening live The GSM module requires a 3 4 4 2V supply 2 Since 3 3V will not be sufficient it will be powered from the 3 8V rail The peak impulse current for this module can be as high as 2A 8 1 6 Bluetooth module The Bluetooth module allows for better recording and more discreet placement of the device since it will enable the device to connect with a small Bluetooth microphone situated anywhere in the room The Bluetooth module requires a 3 6V to 7V su
50. d to SPIBUF register void WriteSPI2 unsigned int data out 19 define OC_IDLE_CON Oxdfff define OC 2 SRC OxfffT7 define OC PWM FAULT PIN DISABLE Oxfffe define PWM SETUP OC IDLE CON amp OC TIMER2 SRC amp OC PWM FAULT PIN DISABLE ATD interrupt control define EnableIntADCl1 asm BSET IECO 13 define DisableIntADCl1 asm BCLR IECO 13 define T4_OFF Ox7fff Timer4 OFF define T4 IDLE CON Oxdfff operate during sleep define T4 GATE OFF Oxffbf Timer Gate time accum off define PS 1 256 Oxffff Prescaler 1 256 define T4 32BIT MODE OFF Oxfff7 define T4 SOURCE INT Oxfffd Internal clock source define T4 SETUP 4 OFF amp TA IDLE amp 4 OFF amp TA PS 1 256 amp T4 32BIT MODE OFF amp T4 SOURCE INT define T4 PERIOD OxOOff define T4 INT PRIOR 5 Oxfffd 101 Interrupt is priority 5 define T4 INT OFF Oxfff7 Interrupt Disable define 4 CONFIG 4 INT OFF amp T4 INT PRIOR 5 define EnableIntT4 asm BSET 11 define DisableIntT4 asm BCLR 11 ECE 477 Final Report Fall 2006 setup c setup c Author Karl Herb This code is derived from modules such as timer h adcl2 h etc included with the compiler Definitions have literally been copied and pasted and used for our setup This way 1 the amount of header files is greatly reduced and 2 only what is necessary is contained herein This setups the timers ATD PWM seria
51. dden in household furniture specifically a lamp The footprint of the device must accommodate this requirement Also no active cooling can be utilized to maintain the stealth silence of the system 3 1 7 Cost Constraints The Digi Spi will be competing in a niche marketing focused on individuals and companies that require high end remote surveillance needs Baby monitoring systems enable ECE 477 Final Report Fall 2006 close range monitoring in the 100 price range but they do not integrate the technology to enable surveillance from anywhere in the world 3 2 Component Selection Rationale 3 2 1 Microprocessor Selection Early in the design process a criterion was created for the selection of the microcontroller First selecting a platform that the team was familiar with was determined to be critical This immediately narrowed the field of microcontrollers to Freescale and Microchip Next to accommodate the buffering and processing of audio the amount of onboard RAM was considered The Freescale MC9S12 E128 has 16K of RAM while the MicroChip dsPIC33FJ256GP710 has 30K of SRAM SPI and RS 232 Serial interfaces are also required but both processors provide ample support for the necessary serial communication and GPIO 8 6 The economic factors of the microcontroller were also carefully weighed The MC9S12 E128 can be purchased from DigiKey for 10 48 while the dsPIC costs 19 80 in single unit quantities The determining factor tho
52. e theData theDatat t F 29 Fall 2006 ECE 477 Final Report Write CRC bytes SPIWrite OxFF SPIWrite OxFF wait to complete status SPIRead while status OxFF status SPIRead SD_Disable wait 8 clock cycles SPIWrite OxFF return 0 internal function definitions this taken from MidiMaestro directly not augmented much unsigned char InitSD void unsigned int i 0 unsigned char status SD_Disable Wait for power to really go down for i 0 i itt for i 0 i itt for i 0 i i for i 0 1 itt Turn on SD Card SD_PowerOn Wait for power to really come up for status 0 status lt 10 status for i 0 i i for i 0 1 itt for i 0 i itt for i 0 i itt We need to give SD Card about a hundred clock cycles to boot up for i 0 lt 16 i SPIWrite OxFF write dummy data to pump clock signal line SD Enable This is the only command required to have a valid CRC After this command CRC values are ignore unless explicitly enabled using CMD59 F 30 Fall 2006 ECE 477 Final Report Fall 2006 unsigned char CMDO_GO_IDLE_STATE 0x40 0x00 0x00 0x00 0x00 0x95 Wait for the SD Card to go into IDLE state i 0 do status SD_WriteCommand CMD0_GO_IDLE_STATE fail and return if i gt 50
53. e local array at the value specified by count like an object s data encapsulation function unsigned char SD_GetSample int cnt return buffer cnt similar to above just adds a single value to the internal buffer F 27 Fall 2006 ECE 477 Final Report Fall 2006 void SD_SetSample int cnt unsigned char sample buffer cnt sample return signal to write the local buffer to the SD card at the block pointed to by the internal pointer void SD_writeCurr void SDWriteBlock curr_block curr block t return signal to read the current pointer s block to the local array void SD readCurr void SDReadBlock curr block curr block t return read a block of 512 bytes SD BLOCK SIZE from the SD card unsigned char SDReadBlock unsigned long block buffer typ theData unsigned char read cmd 6 unsigned char status 0x0 unsigned int offset 0 unsigned char res 1 best to do a quick init in case anything is off while res res InitSD send the read command and the block block block SD_BLOCK_SIZE need to be correct offset read cmd 0 READ CMD read cmd 1 block 5 OxFF000000 gt gt 24 read cmd 2 block amp OxOOFF0000 gt gt 16 read cmd 3 block amp OxOOO0FF00 gt gt 8 read cmd 4 block amp 0 000000 s read cmd 5 DUMMY SD Enable status SD WriteCommand read cmd if
54. e main environmental impact of the product is EMF from the wireless modules This so called eSmog has an environmental impact in the sense that it harms living organisms including humans in the environment 26 The radiation of EMF can cause breaks in DNA sequences and inhibit the body s ability to repair these breaks 26 For this reason there are the ethical liability and labels mentioned above These also double to warn the user that the device can be harmful Unfortunately the data for EMF harm is still not fully backed but it could be a potential risk In addition our device is small and only uses Wi Fi Bluetooth and cellular modules These will not come in close proximity to a human as a cellular phone would If this environmental need would be addressed and the device is manufactured in addition to the labeling it would be best to include an optional Ethernet connection with the ability to disable the wireless Over time the device will breakdown and when it is time for disposable it would be best to recycle the device Efficient disposal is an important step to prevent potentially harmful e waste from just being put in the trash This is evident from a military document summary that states PCBs generally have no usefulness once they are removed from the electrical component in which they were installed 28 In our case this would be when it is no longer powered and the board has burnt out The large amounts of lead and the
55. e pointer while near ndata is the default setup for all values Therefore only the sample buffer needs a special setup Table 10 1 Memory Setup Item Location Compiler Call Executable Code text Setup by the C30 compiler Global Variables ndata _attribute_ space ndata Sample Buffer far _attribute_ space far Stack Stack Setup by the C30 compiler 10 2 Code Organization The code is ultimately interrupt driven with the main signal processing algorithm embedded into the main program loop The design is partially polling as the main program loop waits for a signal from the interrupt service routine that a set can be processed Therefore this is a flag driven or a hybrid organization of the software For maximum organization and scale ability the main program is designed as a state machine seen in Appendix F In the appendix section is also the code listing i e the tree Several files were used in addition to main for setup LCD I O and SD I O These contained the low level routines necessary and presented the main program with a high level interface to achieve the desired result To aid in the design timers are used to achieve functionality Timer is used to setup the heartbeat debug that pulses an LED every 0 5 second This insures the board is working Timer 2 is used by the PWM allowing it a 10 bit sensitivity and 8 kHz frequency Timer 3 drives the ATD and its time out triggers a sample every 0 125 m
56. energy used to make the device should not be wasted Instead companies exist that recycle the device such as NEC Corp in Japan 29 This plant separates the components of the PCB and materials including copper are reclaimed from the board This is in the hopes of reusing the materials Clearly this is not an inexpensive procedure and for a single board this would not be the best solution For a set of manufactured boards it would be ideal For this reason the user manual will contain a return 22 ECE 477 Final Report Fall 2006 to manufacturer label for proper disposal and a warning label will be on the package as well This way the PCB can be recycled or taken care of if another avenue exists at the time For disposal of the remaining device i e the lamp and plastics it would be best to recycle these items Unfortunately much of the materials are thrown away in American society but it would be best to reuse any parts such as screws and spacers for future use Therefore the disposal of the entire package will be marked as returnable to the manufacturer for proper disposal In order to not be offensive and incur any costs the warning label is only a suggestion for a marketable product But this is a single prototype and therefore the return to manufacturer is a demand 6 3 Summary As is shown the Digi Spi has several ethical and environmental issues that must be addressed Its impact ranges from basic PCB recycling to the eth
57. equency band limited energy and the history of the smoothed frequency band limited energy within the signal The use of the variance allows detection which is relatively independent of an absolute signal to noise ratio with the signal and allows accurate detection within a wide variety of backgrounds such as music motor noise and background noise such as other voices The third patent detects speech based on frequency band energies In this case Claim 2 is the most important It mentions a means for selecting portions of the signal having frequencies within a pre selected range and a means to determine the values of frequency band limited energy 19 12 ECE 477 Final Report Fall 2006 4 2 Analysis of Patent Liability 4 2 1 Literal Infringement According to an article from JOM about patent infringement Every requirement of each claim must be considered to see if each thing set out in the claim also appears in the accused practice If one or more things set forth in a claim is not present in the practice being reviewed there is no infringement of that claim 20 Using this as a basis the most similar and relevant claim for each patent is considered and then it is determined whether what is set out in that claim also appears in the Digi Spi If the most similar and relevant claim differs from the product being considered then no literal infringement exists The most similar claim for the first patent discussed mentioned energy cha
58. ffer is ready for more data while SPIISTATbits SPITBF this taken from MidiMaestro directly not augmented much unsigned char SPIRead void unsigned char data if SPIISTATbits SPIRBF already have some data to return don t initiate a read data SPIISTATbits SPIROV 0 return data We don t have any data to read yet so initiate a read SPI1BUF OxFF write dummy data to initiate an SPI read while SPIISTATbits SPITBF wait until the data is finished reading data SPII1BUF SPIISTATbits SPIROV 0 return data end SD c F 33 ECE 477 Final Report Fall 2006 LCD h LCD h Authors Brad Sokola Justin Lanning This contains the definitions and interface necessary for working with the LCD The necessary cmds are hardcoded into main c Look at it for information finclude p33FJ256GP710 h internal defines define CLEAR LCD 0500000001 define RETURN HOME LCD 0500000010 externally visible functions void LCD init void void LCD put char char ch void LCD cmd char ch void LCD reset time void void LCD update void void LCD set src char src void LCD put string char string void LCD set mic char mic void LCD reset void F 34 ECE 477 Final Report Fall 2006 LCD c LCD c Authors Af MEE char char char char char char char void Brad Sokola Justin Lanning
59. fine pitch pines of the dsPIC TQFP Power traces will be larger a minimum of 70 mils to handle up to 3 amps of instantaneous current 37 The trace widths are calculated using the PCB manufacturer s online calculator First the trace area is calculated 192 9 square mils for 3 amps using 2 oz copper and a 10 degree temperature rise and then the associated trace width 70 mils is computed Power traces will also be routed in a hub and spoke configuration to avoid inductive loops 38 To reduce power supply noise bypass capacitors will be placed at the power supply and as close as possible to all active devices 36 Care will be taken to reduce the lead length on the bypass capacitors located at the input voltage pins of peripheral components The Ezurio Bluetooth module and WiPort Wi Fi server have internal voltage regulation so bypass capacitors would not be necessary for these devices However bypass capacitors will be utilized in this design to maintain a stable power rail 4 1 Specific bypass capacitor requirements for the power supply and GM862 GSM cellular modules are discussed in the power supply requirements section of this document Secure and stable physical mounting of the three wireless modules will be important The Ezurio Bluetooth module is contained on a separate PCB that will mate with the core logic board through a 40 pin connector 4 Drill holes will be necessary for plastic stand offs that secure the Bluetooth module
60. ginal and has not been kept uptodate and therefore the code or variable has fallen out of importance Wi include SD h need this to call appropriate functions for debug SCI include setup h include LCD h so can interrupt when SD card removed include LCD h internal macros some legacy define HEX 16 define READ CMD 17 define DUMMY OxFF define START BLOCK TOKEN R1 Response Codes from SD Card Product Manual v1 9 section 5 2 3 1 define R1 IN IDLE 5 1 0 The card is in idle state and running initializing process define R1 ERASE RESET 1 1 An erase sequence was cleared before executing because of an out of erase sequenc command was received define R1 ILLEGAL COMMAND 1 2 An illegal command code detected define R1 COM ERROR 1 lt lt 3 The CRC check of the last command failed define ERASE SEQ ERROR 1 4 An error in the sequence of erase commands occured define R1 ADDRESS ERROR 1 5 A misaligned address which did not match the block length was used in the command define PARAMETER 1 6 The command s argument e g address block length was out of the allowed range for this card ports redefined for descriptive use define SD CS PORTCbits RC4 define SD CS DIR TRISCbits
61. h the description of the VAD software is still sparse it does state that the VAD algorithm analyses voice activity to detect silence intervals The detecting of silence intervals would seem to indicate some type of threshold comparison 4 1 4 US Patent number 6 453 285 Issued September 17 2002 Speech activity detector for use in noise reduction system 17 A system and method for removing noise from a signal containing speech or a related information carrying signal and noise A speech or voice activity detector VAD is provided for detecting whether speech signals are present in individual time frames of an input signal The VAD comprises a speech detector that receives as input the input signal and examines the input signal in order to generate a plurality of statistics that represent characteristics indicative of the presence or absence of speech in a time frame of the input signal and generates an output based on the plurality of statistics representing a likelihood of 11 ECE 477 Final Report Fall 2006 speech presence in a current time frame and a state machine coupled to the speech detector and having a plurality of states The state machine receives as input the output of the speech detector and transitions between the plurality of states based on a state at a previous time frame and the output of the speech detector for the current time frame This patent uses a variety of statistics to determine the likelihood of s
62. have been specified to be a minimum to 70 mils to handle 3 amps of current As an added safety factor and per the suggestion of the course staff the traces will be enlarged to 100 mils 37 The traces to high power components like the GM862 and WiPort must also be kept as short as possible Although the voltage drop and power loss across a long trace might be acceptable for a device that is not battery powered the induced noise is not tolerable The current impulses from the GM862 occur at a frequency of 216 Hz 2 Care must be taken to insure that noise from these impulsive current spikes does not affect the rest of the embedded system To minimize noise a common ground plane will be utilized This introduces some complexity in the layout since more signals will have to be routed on a single layer but will provide better noise tolerance for our mixed signal application Care in ground plane routing though must be taken to insure that high current return paths do not cross noise sensitive lines like the analog audio signal lines near the microcontroller and GM862 GSM module 36 As previously mentioned the power supply system will utilize bypass capacitors placed close to all active components Specifically the GM862 requires a low ESR bypass capacitor located very close to the part to reduce the current absorption peaks a 100 uF tantalum capacitor is recommended 2 The PCB layout strategy will prioritize the close placement of all these bypas
63. he final algorithm used only 512 bytes of data roughly 0 06 seconds of audio to make a determination A circular buffer of at least 2 blocks is necessary to allow the processing of each block to be completed without having to worry about data being over written before it is stored to the external memory card This means that the audio processing requires a minimum of 1024 bytes of memory The signal processing algorithm and output to the SD card are embedded into the main program loop while the sample buffering is interrupt driven When a full block is ready to be processed a flag is set by the interrupt and processed in the main loop The signal processing ECE 477 Final Report Fall 2006 algorithm consists simply of comparing the average energy of the block to a threshold set at system start ups and at resets From an experimental test of our code the comparison and a 512 byte write to the SD card took roughly 10ms to complete Since it takes roughly 60ms for a block to be sampled this gives plenty of time for a block to be processed before a new one is ready 3 1 2 Interface Requirements To accommodate the spectrum of peripherals external to the microcontroller a variety of general purpose I O systems will be necessary A summary of the I O requirements is provided in Figure 1 The SPI bus is utilized to interface the microcontroller with the WiPort Wi Fi Server Telit GSM Cellular Module and Secure Digital Memory Card 1 2 3 Commun
64. his a warning label will be placed on the device noting the EMF factor and in the user manual a note will be made stating that while the device abides by all relevant regulations regarding EMF emissions there is still a potential hazard 6 2 Environmental Impact Analysis This device is designed to be a novelty item and not for a specific portable or professional application Therefore the worst environmental impacts come from the manufacturing and disposal of the PCB and components During manufacturing the environmental impact of the device is due to the PCB manufacturing PCB manufacturing consists of etching of the traces onto a metal This uses 21 ECE 477 Final Report Fall 2006 numerous natural resources including metals copper gold nickel and tin and water 27 In addition the process generates large amounts of metal bearing effluent solutions that require expensive treatment before they are discharged into the environment 27 Fortunately this product is only a prototype but if the product were put into production it would be necessary to consider the cost of alternative PCB manufacturing technologies that reuse the manufacture metals and reduce pollution With effective capturing procedures the large amount of metal bearing solution is less likely to be released into the environment and a portion can be reused for another PCB Once the PCB is etched and populated it is operational During the operational phase th
65. ic can be viewed in Appendix A These blocks include Microcontroller and Off Board Peripherals A Audio and GPIO B On Board Wireless Modules C and Power Management D The following criticality definitions will be used for this analysis High criticality is defined as anything potentially harmful to the user this type of failure has a Ap lt 10 Medium criticality is defined as any failure that affects the device s primary function of recording speech or causes irreparable damage to any component this includes any failures in the range of 10 lt Ap lt 10 Finally low criticality is defined as any failure that partially limits device function but does not affect the recording of speech or causes reparable damage this includes failures with 10 lt lt 107 A full FMECA report can be viewed in Appendix G after investigation of this report it is obvious that the Power Management Block is most critical to safety of operation Every failure within this block has a rating of at least medium criticality because of the block s ability to propagate its failures to other systems Also it should be noted that the three failures of Block D can be viewed as six failures since there are two different supply voltages Depending on which supply voltage is affected the consequences throughout the circuit are quite different Within this block a way of addressing the high criticality failure of excess voltage would be to place a zener
66. ication with the Ezurio Bluetooth Module was designed to be accomplished with the standard RS 232 SCI protocol 4 Two general purpose digital inputs were used for operator interface control The operator interface display 16 x 2 LCD utilized an 8 bit parallel interface 5 Finally an analog ADC input accommodated microphone input while a PWM output allowed for digital to analog conversion The design requires a total of 27 I O pins Two separate SPI lines were utilized because the GSM module s SPI interface is implemented in Python and only allows operation in master mode So the microcontroller has one SPI port configured in master mode and one in slave mode Peripheral Description Interface Number of Pins Wiport 802 11b g Wi Fi Server SCI RS 232 2 input output Hitachi 16x2 LCD Parallel 11 8 data lines chip select clock Telit GSM Cellular Module SPI 4 input output chip select clock Ezurio BISM2 Bluetooth Module SCI RS 232 2 input output Secure Digital Card SPI 4 input output chip select clock Maxim Switch Debouncer GPIO 2 CMOS level Analog Audio Input A to D 1 Analog Audio Output PWM 1 Figure 3 1 I O Requirements ECE 477 Final Report Fall 2006 3 1 3 On Chip Peripheral Requirements The on chip peripheral requirements are dictated by the selection of external components outlined in this document As described in section 2 2 and Figure 1 1 five on chi
67. ics of recording sound data With a correct design focus for amateur use and warning labels this device will not pose an ethical liability By adding to that a non battery design involvement in device disposal and alternative manufacturing methods the device will have a low impact on the environment as well 23 ECE 477 Final Report Fall 2006 7 0 Packaging Design Considerations The DigiSpi is enclosed inside a typical household lamp The lamp will feature a hidden compartment where the DigiSpi LCD can be viewed SD Card accessed and recording turned on off by way of push buttons 7 1 Commercial Product Packaging After considerable market research two families of similar product types emerged the compact digital voice recorder and the ultra high frequency transmitter receiver surveillance system The specific products chosen to represent these types are the Spytronix 33hr Mini Digital Recorder 13 and the MSCSpytek UHF Transmitter Receiver 30 7 2 Spytronix 33hr Mini Digital Recorder The Spytronix Mini Digital Recorder as seen in Figure 1 is a very compact and portable voice recorder The design is very simple having only one external push button and a small one line LCD display which shows the current recording status Also not visible in the graphic is the USB jack which is used to download the recorded messages to the user s PC and the built in speaker which can be used for instant playback The device runs on 2 AA
68. ign constraints the group considered will be discussed 3 1 Design Constraint Analysis The following sections summarize the computation interface on chip and off chip peripherals power cost and packaging constraints and requirements for the project All of these criteria were considered when selecting parts and designing the embedded application The focus of this project s constraints was interface and peripheral requirements Interface requirements were critical due to the number of different peripherals that were being supported Serial and SPI capabilities are important for communication between these devices Microcontroller selection was also heavily considered to insure that signal processing algorithms for speech processing could be completed in real time 3 1 1 Computation Requirements The computational requirements of the project can be broken into digital input output sample buffering and signal processing computation and transfer to external memory In order for the project to be useful as an audio listening and processing device it is necessary for the embedded application to store audio samples for future calculations The samples will be 8 bits wide Samples will be buffered into SRAM with a frequency of 8 kHz The speech detection algorithm makes a determination of whether speech is present on a block by block basis The initial version of the algorithm used up to half a second or 4000 bytes of data to make a determination T
69. illisecond Timer 4 is used to poll the pushbuttons and this is done every 2 milliseconds For interrupts Timer 2 and 3 are used to control the ATD sample and PWM frequency so only Timer 1 and Timer 4 have user defined interrupts Timer 1 toggles the LED on port and timer 4 looks for a button to toggle from low to high and back to low meaning it has been pushed When the red pushbutton on port RD2 is pushed it sets a src_flag and the black 36 ECE 477 Final Report Fall 2006 pushbutton on port RD1 sets a reset_flag These are used to reset the device or toggle its mode In addition the ATD sample conversion to an unsigned integer value begins once a sample is obtained The completion of the conversion causes an interrupt Within this ATD interrupt is the buffering of the sample and or output of a respective data depending on the operation setup see more in subsequent paragraphs When 512 bytes of data are read or written from the buffer a sample_flag is set to signal for more data or there is data that could potentially written to the SD card Block diagrams for each of these interrupt service routines are seen in Appendix F 10 3 Processing Summary The software has three different states The first is a reset mode and is entered whenever a state is finished and the reset_flag is set The reset mode sets up the registers initializes the SD cards sets the timing of the registers and timers and sets up the buffers If the source
70. ine NUM_BUFF 6 define PIVOT 5 Zero Voltage Level aka threshold define ZERO_LEV 0x73 Controls for the buffering A large array is mantained of the specified number of buffers each with a block size for SD card I O see SD h for SD_BLOCK_SIZE define The ISR_ptr is controled ISR and SD ptr is controlled by the main polling loop and is prepped on its first necessary use cnt is used in the AD1 ISR int ISR_ptr 0 int SD_ptr 0 int cnt 0 F 9 ECE 477 Final Report __attribute__ far unsigned char buffers NUM BUFF SD BLOCK 5171 Fall 2006 flags for prepping SD_ptr and for threshold setup int first 1 Controls whether time displayed gets updated on LCD char threshold_setting 0 nothing to respond to SD h SD c counts for timer 1 int timerl 0 int prevRD2 1 active low int 1 active low flags for transitions RUE Need to address like IF FALSE enum flag typ TRUE FALSE Jj Ee RUE if want to change the SRC of the and buffering I O enum flag_typ src_flag RUE to get or set more data to from SD enum flag_typ sample_flag RUE if a reset is desired enum flag typ reset flag RUE if buffer overrrun enum flag typ err flag PWM src control MMC is confusing but
71. inline setup inline start inline stoplR inline runIR inline buffer output uchar algorithim Set Threshold setup CD init setup GPIO LCD put char setup timer LCD cmd char toggle LED LCD reset set DutyCycle uint LCD update run timers LCD set src char run periph LCD put string char enableATD LCD set mic char disableATD char global curr SD BLOCK SIZE uchar setup SDSPI SD uchar SD GetSample int SD SetSample int uchar SD writeCunt SD E uchar buffer SD BLOCK SIZE char global ten sec ulong curr block inline setup PLL inline open timers inline config timers inline setup PWM inline setup inline config char global min char global ten min char global hr char global ten hr char global day F 1 ulong total blocks uchar SDReadBlock ulong uchar SDWriteBLock ulong InitSPI uchar InitSD uchar 50 WriteCommand uchar uchar SPIRead SPIWrite uchar ECE 477 Final Report Fall 2006 Main Program Loop State Machine Flow Chart MAIN PROG LOOP reset_flag true cum state RESET Switch state UPDATE CODE cur state cur state RUN RUN cum state cur state UPDATE RUN emm emm em emm emm emm emm ECE 477 Final Report RESET CODE Flow Chart Set Thresho
72. kely be a niche product so economic gain from any type of infringement suit would be small for the other company Second there is a wide range of prior art involving speech detection utilizing energy thresholds making any case of infringement difficult 14 ECE 477 Final Report Fall 2006 5 0 Reliability and Safety Analysis When considering the reliability of the Digi Spi components it is logical to immediately look into the three wireless modules utilized in its design However due to the black box nature of these devices they do not lend themselves to easy reliability analysis and have therefore been excluded from the following report The remaining components within the Digi Spi that will pose reliability issues are the microcontroller LT1528 LDO voltage regulator LT1121 LDO voltage regulator and microphone pre amplifier The failure rate and mean time to failure will be discussed for each of these microcircuits as well as possible measures to increase their reliability Essential to the safety and quality of any device is prior consideration of how this device could possibly fail By doing this analysis during the design process an engineer can take measures to ensure that their product fails in a safe and predictable manor This analysis is best done by breaking the device schematic into functional blocks and looking at failures within each section The blocks to be considered within the Digi Spi are the microcontroller and
73. l only for debug SPI for the GSM and GPIO except for the LCD include setup h include LCD h internal definitons for ATD setup define define SAMP BUFF SIZI NUM CHS2SCAN debug functions void printhexdigit unsigned char digit global for GPIO with the LED char global curr internal inline functions inline void setup PLL pg 153 fig 8 2 in osc doc also have divide by 4 factor not shown exp shows a IF of 66 6MHz so a clock freq of 33 3MHz _PLLPRE 2 _PLLDIV 150 _PLLPOST 2 timing periods and op factors inline void open timers TMR1 0 PERIOD T1_SETUP TMR2 0 PR2 T2 PERIOD T2CON T2_SETUP TMR3 0 PR3 T3 PERIOD T3CON T3_SETUP TMR4 0 PERIOD T4CON T4_SETUP interrupt setup inline void config timers IFSObits T1IF IPCObits T1IP IECObits T1IE IFSObits T2IF T1 CONFIG amp 0 0007 CONFIG amp 0 0008 gt gt 3 0 0 20 ECE 477 Final Report IPClbits T2IP T2_CONFIG amp 0x0007 IECObits T21E T2 CONFIG amp 0 0008 gt gt 3 IFSObits T3IF 0 IPC2bits T3IP T3 CONFIG amp 0x0007 IECObits T3IE T3 B FIG amp 0 0008 zz IFSlbits T4IF 0 IPC6bits T4IP 4
74. ld LCD set LCD set src R buffer output ECE 477 Final Report Fall 2006 RUN CODE Flow Chart sample_flag false algorithm 1 SD readCurr coutner 0 counter lt SD BLOCK SIZE counter SD BLOCK SIZE SD SetSample caunter butters SD prricounter counter courier 1 SD SetSample caunter butters SD pirfcounter Caister counter 1 D ptr SD ptr 1 96 NUM BUFF F 4 ECE 477 Final Report UPDATE CODE Flow Chart SD_setStart src_pwm MMC buffer output first 1 SD ptr 7 1 ISR 0 ECE 477 Final Report Fall 2006 ATD Conversion Interrupt Service Routine Flow Chart sat DutyCyclot set DutyCyde ADCTBUFO buffers ISR perdent bufferstiSR opreegt ADCIBUFO gt gt 2 sample bufers ISR_ptrfcnt sample gt ZERO_LEV energy energy test ISR pir ISR 1 NUM BUFF yes first false 50 0 D buffer cnt buffer crc 1 temp E energy temp 2 zerocross F 6 ECE 477 Final Report Fall 2006 Timer 1 heartbeat LG second Interrupt Service Routine Flow Chart TIF 0 TMR1 0 toggie LERN timart_ent 0 LCD update ECE 477 Final Report Timer 4 pushbutton sample Interrupt Service Routine Flow Chart _RD2 1 AND prevRD2 _RD1 1 AND RD1 prevRD1 prevRD2 RD2 prevRD1 RD1
75. lity I completed three revisions of the board following some major schematic changes With the assistance of Brad Sokola I constructed the lamp housing and hidden operator interface within the lamp This task included lots of woodworking cutting staining and wiring of the components Besides these main focus areas I assisted with various tasks as issues and problems arose I provided assistance with the initial schematic did significant research on the Bluetooth integration and PCM codec selection soldered the majority of our components on the PCB provided debugging assistance with the SPI initialization and LCD contrast control and debugged the issues plaguing the power up control of our GSM module A 4 Contributions of Justin Lanning Throughout the semester I took on a number of roles varying from both hardware and software Aside from the individual homework s that I completed the first half of the semester was spent mostly assisting with schematic creation and circuit design When it came time to do the layout Brad and I assisted Warren by creating and verifying dimensions on the custom ECE 477 Final Report Fall 2006 footprints required for our design Also when the team divided up the peripherals I became the WiPort expert and I spent time working with this device on a development kit that we had purchased I was able to setup the wireless web server and connect to it I embedded on the server a Java applet which created a
76. ll 2006 25 R B K Dewar and R Chapman Building secure software Your language matters Military Embedded Systems Winter pp 30 33 2006 http www mil embedded com PDFs AdaCore Win06 pdf 26 David Benjamin Is EMF radiation the cigarette of the 21 century EE Times Online Online Document 13 February 2007 accessed February 21 2007 http www eetimes com showArticle jhtml articleID 197005857 amp printable true 27 intellectuk org World First makes printed circuit board production more sustainable Online Document unknown publication date accessed February 21 2007 http www intellectuk org markets pcb_production asp 28 Printed Circuit Board Recycling Overview Online Document unknown publication date accessed February 21 2007 http p2library nfesc navy mil P2 Opportunity Handbook 2 II 8 html 29 Techmonitor net Waste Management Jan Feb 2006 Electronic Wastes Recycling printed circuit boards Online Document 2006 accessed February 21 2007 http www techmonitor net techmon 06jan feb was was electronic htm 30 MSCSpytek UHF Crystal Controller Transmitters and Receivers Online Document Jan 27 2007 accessed Jan 27 2006 http www mscspytek com uhf spy ing equipment htm 31 Microchip com dsPIC30F3014 4013 Data Sheet Online Document unknown publication date accessed February 07 2007
77. n date accessed April 7 2007 http www keenzo com showproduct asp ID 800524 amp ref FRGO 17 Anderson David V Speech activity detector for use in noise reduction system US Patent 6 453 285 September 17 2002 18 Vergin Julien Rivarol Speech detection system and method US Patent 6 757 651 June 29 2004 19 Reaves Benjamin Kerr Speech detection device US Patent 5 826 230 October 20 1998 20 Blenko Walter J The Doctrine of Equivalents in Patent Infringement JOM vol 42 5 59 1990 http www tms org pubs journals JOM matters matters 9005 bm 21 Department of Defense Military Handbook Reliability Prediction of Electronic Equipment Online Document 1991 Available http cobweb ecn purdue edu dsml ece477 Homework Fall2006 Mil Hdbk 2 1 7F pdf 22 Maxim Low Cost Single Dual Input Fixed Gain Microphone Amplifiers with Integrated Bias Online Document 2003 Available http datasheets maxim ic com en ds MAX9812 MAX9813L pdf 23 Linear Technology LT1121 Micropower Low Dropout Regulators with Shutdown Online Document 1994 accessed April 9 2007 http www linear com pc downloadDocument do navId H0 C3 P1370 D2188 24 Freescale Semiconductor MC145481 PCM Codec Filter Online Document 1998 accessed April 9 2007 http www freescale com files timing interconnect access doc data sheet MC145481 pdf 42 ECE 477 Final Report Fa
78. n in English Finally a Wi Fi module the Lantronix Wiport was selected based on cost lower power and interface flexibility ECE 477 Final Report Fall 2006 4 0 Patent Liability Analysis There are a few areas of potential patent infringement The primary area for infringement is the speech detection algorithm however the file format used to store audio and the file system used on the external memory will also be considered The rest of the device s functionality comes primarily from interfacing with components that would have any potential licensing fees already included in their price Since the speech detection functionality appears to have the most potential for infringement this report will focus primarily on that aspect of the device However a brief analysis regarding the file format and file system is included The system will store the sample values directly onto the SD card When the user removes the SD card and uses the card reader and software provided the sample values will be written to a Sun Audio file for the user to listen to The Sun Audio au file format is an open file format so there should not be any potential for infringement The Digi Spi device will not be utilizing a recognized file system on the SD card but instead will simply be writing directly to memory and then will have a card reader and software on the user s computer that will output the audio files Since no real file system is being used there is no w
79. ng mode to playback mode by pressing one push button The other button allows the user to reset the device which returns the up time to 0 and initializes any SD card operations to start at the first block of data 4 An ability to save speech signals to external memory An SPI interface to the SD card is implemented and this is shown by successfully initializing the card outputting data to it and re obtaining it This is demonstrated alone with demonstration boards and also in the project by saving the audio signal from the A to D and then being able to re obtain it for output on the PWM 5 An ability to play back the recorded sound via headphone jack or line level output The Digi Spi device is able to play back what is stored on the SD card through the PWM pin output electrically connected to a low pass filter and a headphone jack This is demonstrated by leaving the device in recording mode and speaking into the microphone Then the device is switched to playback mode and the SD card s recorded speech is heard on the headphones ECE 477 Final Report Fall 2006 3 0 Constraint Analysis and Component Selection The Digi Spi device was designed to integrate a microcontroller with digital signal processing capabilities an LCD driven user interface a Bluetooth host controller an 802 11b g wireless web server a GSM Cellular Modem an SD Memory Card interface and analog line level input output In the following section the important des
80. nge and spectral deviation change statistics The Digi Spi device uses only an average energy statistic over a block of data with no carry over between blocks Thus it does not literally infringe on this claim The most similar claim for the second patent discussed mentioned a threshold comparison and the generation of a predictive signal for comparison The Digi Spi does not generate a predictive signal of any kind so it does not infringe on this claim The third patent considered mentions detection based on frequency band energies Its first claim refers to a means for determining a variance of smoothed frequency band limited energy and means for determining the beginning and ending points of speech within the signal based on the variance of the smoothed frequency band limited energy and past history of the smoothed frequency band limited energy 19 The Digi Spi device only uses an energy threshold comparison This does not include what is mentioned in claim 1 and thus does not literally infringe Based on this analysis the Digi Spi device does not literally infringe on any of the speech detection patents discussed 4 2 2 Infringement under the Doctrine of Equivalents Under the doctrine of equivalents a device can be considered to be infringing on a patent if it performs substantially the same function in substantially the same way even if it does not literally infringe on the claims The first patent analyzed 17 mentions using energ
81. nign condition TQ 10 00 Commercial component TL 1 00 Years in production 2 2 0 5 97 Failures Million Hours 1 675 5 hrs 19 12 years Table 5 1 dsPIC33FJ256GP710 6 MTTF Parameters Parameter Value Justification C 0 02 Assumed Linear MOS device of Transistors 264 TT 32 00 BiCMOS T 150 degrees C 16 ECE 477 Final Report 0 002 Hermetic 6 pin SC70 6 package eq 1 2 8 E 4 641 08 0 50 Assumed ground benign condition TQ 10 00 Commercial component TL 1 00 Years in production 2 2 0 6 41 Failures Million Hours MTTF 1 56 5 hrs or 17 81 years Table 5 2 MAX9812L Microphone Pre Amplifier 22 MTTF Parameters Parameter Value Justification Ci 0 01 Linear MOS device of Transistors assumed to be 100 TT 180 Linear MOS T 150 degrees C C5 00092 Hermetic 3 pin SOT23 6 package eq 1 2 8 E 4 341 08 TE 0 50 Assumed ground benign condition TQ 10 00 Commercial component TL 1 00 Years in production 2 2 0 18 00 Failures Million Hours MTTF 5 56E 4 hrs or 6 34 years Table 5 3 LT1121 LDO Linear Regulator 23 MTTF Parameters Parameter Value Justification 0 01 Linear MOS device of Transistors assumed to be lt 100 TT 58 0 Linear MOS T 125 degrees C C5 0016 Hermetic 5 pin DD package eq 1
82. ntT2 asm BCLR 7 timer 3 defines setup for tick every 8 kHz use with ATD define T3_OFF Ox7fff Timer4 OFF define T3 IDLE CON Oxdfff operate during sleep define T3 GATE OFF Oxffbf Timer Gate time accum off define T3 PS 1 1 Oxffcf Prescaler 1 1 define T3_SOURCE_INT Oxfffd Internal clock source define T3_SETUP 3_OFF amp T3_IDLE_CON amp T3_GATE_OFF amp T3_PS_1_1 amp T2_32BIT_MODE_OFF amp T3_SOURCE_INT define T3_PERIOD OxOfff define T3 INT OFF Oxfff7 Interrupt Disable define T3 INT PRIOR 2 Oxfffa 011 Interrupt is priority 3 F 18 ECE 477 Final Report define T3_CONFIG define DisableIntT3 3_INT_OFF amp T3_INT_PRIOR_2 asm BCLR ECO 7 timer 4 defines for pushbutton sampling every 2ms Fall 2006 PWM defines external function definitions Ky void void void void void void void void void void void void setup_mem void setup_GPIO void setup_timing void setup_periph void toggle_LED void set_ run_timers void run_periph void i i DutyCycle unsigned int printbyte unsigned char prints char enableATD void disableATD void ReadSPI Read byte word from SPIBUF register unsigned int ReadSPI2 WriteSPI Write byte wor
83. obal_sec 0 global_ten_sec 0 global_min 0 global_ten_min 0 global_hr 0 global_ten_hr 0 global_day 0 return void LCD set src char src Update Recording Status LCD_cmd 0x88 sets cursor at Rec Playback place if src P Playback mode LCD_put_string Ply else if src R Recording mode LCD_put_string Rec else if src L Listening but not recording LCD put string Lis else Off LCD put string Off return void LCD_set_mic char mic Update Microphone Status LCD_cmd 0x86 sets cursor at Microphone place LCD_put_char mic return void LCD gsm stat char gsm Update Microphone Status LCD cmd 0x8C sets cursor at GSM place switch gsm case 0 LCD_put_string NoS break case 1 LCD put string Con break case 2 LCD put string Sch break case 3 LCD put string NoS break F 37 Fall 2006 ECE 477 Final Report Fall 2006 case 4 LCD_put_string Ukn break case 5 LCD put string Rom break default LCD put string Off break return void LCD update void global sec if global sec 10 global_sec 0 global_ten_sectt if global ten sec 6 global_ten_sec 0 global_min if global_min 10 global_min 0 global_ten_mint if global ten min 6 global_ten_min 0 global_hr if global_hr 10
84. of the DigiSpi s other large parts are not onboard i e LCD SD card and therefore do not have a large influence on the size of the board The rest of the board is taken up primarily by smaller passive components regulators and IC s and while they individually do not have a large effect on board size they should be factored in collectively when making a PCB size estimate 26 ECE 477 Final Report Fall 2006 7 6 Summary Taking into account the desire to use AC power the PCB size and the need to mask the device s true function the best packaging design for the DigiSpi is to hide it in a common household item that is large enough to hide all internal components and antennas The lamp is an ideal choice for this because it can be designed in a number of ways that can house the DigiSpi hardware While this is quite different than other products on the market the DigiSpi still has some similarities in packaging design However its increased functionality requires a larger PCB and thus it cannot be packaged as compactly as other products 27 ECE 477 Final Report Fall 2006 8 0 Schematic Design Considerations This useful embedded device consists of a number of different components therefore several design considerations must be examined The primary considerations considered are that the power circuitry must be able to supply the 3 voltages required 3 3V 3 8V and 5V and the microcontroller must be interfaced using a variety of
85. ondary prescaler 1 1 SPI1CON1 0x007C 2 0x0000 5 15 0 8000 enable SPI port this taken from MidiMaestro directly not augmented much unsigned char SD WriteCommand unsigned char cmd unsigned int i unsigned char response unsigned char savedSD_CS SD_CS SD Card Command Format from Section 5 2 1 of SanDisk SD Card Product Manual v1 9 Frame 7 0 Frame 6 1 Command 6 bits Address 32 bits Frame 0 1 Set the framing bits correctly never change cmd 0 1 lt lt 6 cmd 0 amp 1 lt lt 7 cmd 5 1 0 Send the 6 byte command SD Enable for i 0 lt 6 i SPIWrite cmd Wait for the response i 0 do response SPIRead if i gt 60000 instead of 100 F 32 Fall 2006 ECE 477 Final Report break itt while response OxFF SD Disable Following any command the SD Card needs 8 clocks to finish up its work Fall 2006 from SanDisk SD Card Product Manual v1 9 section 5 1 8 SPIWrite OxFF SD_CS savedSD_CS return response this taken from MidiMaestro directly not augmented much void SPIWrite unsigned char data DO NOT WAIT FOR SPITBF TO BE CLEAR HERE write data for some reason it doesn t work on this side of th Write the data SPIIBUF data Wait until send bu
86. p peripherals were necessary SPI RS 232 Serial 1 channel of 10 bit ATD 1 channel of 8 bit PWM and 13 channels of general purpose I O 3 1 4 Off Chip Peripheral Requirements To provide the extended and flexible functionality of the embedded system several off chip peripherals were necessary Wireless communication was designed to be managed through three off chip devices The WiPort 802 11b g Wi Fi Server the Telit GSM Cellular Module and the Ezurio BISM2 Bluetooth Module 1 2 4 A Secure Digital SD Card provides extended non volatile memory for audio storage 3 3 1 5 Power Constraints Again the variety of embedded components created several power management constraints The Wiport Wi Fi Server Bluetooth Module and dsPIC Microcontroller can all operate at a nominal 3 3V input 1 4 6 The GSM cellular though must have a voltage supply of 3 4 to 4 2 volts 2 Finally the Hitachi LCD operates at 5V 5 Special care must also be taken to accommodate large power consumption spikes when the wireless radios are transmitting The WiPort and GSM Cellular modem can have current pulses of 400 and 1900 milliamps respectively 1 2 The embedded system will be stationary and powered through a wall wart and three linear regulators running at 3 3V 3 8V and 5V The 3 3V and 3 8V are derived from two LT1528s 7 The 5V is provided by an LT1121 23 3 1 6 Packaging Constraints This surveillance system is intended to be hi
87. peech The key claim for this patent is claim 1 Claim 1 describes these statistics as including an energy change statistic and a spectral deviation change statistic 4 1 5 US Patent number 6 757 651 Issued June 29 2004 Speech detection system and method 18 The method first receives a sound signal and determines 1f the energy value of the sound signal is above a threshold energy value If the energy level of the signal is above the threshold energy value the method determines a predictive signal of the received signal subtracts the predictive signal from the signal and determines if the result of the subtraction indicates the presence of speech If it is determined that no presence of speech is indicated the threshold energy value is set to the energy level of the present received signal If it is determined that the result of the subtraction indicates the presence of speech the received signal is sent to a speech recognition engine The second patent detects speech based on an initial threshold and generation of and comparison to a predictive signal The key claim for this patent is claim 1 This claim mentions using a threshold and also using a prediction algorithm to determine if the audio contains speech 4 1 6 US Patent number 5 826 230 Issued October 20 1998 Speech detection device 19 The device detects the beginning and ending portions of speech contained within an input signal based on the variance of smoothed fr
88. pply so it will be 29 ECE 477 Final Report Fall 2006 supplied by the 3 8V rail 4 It will communicate with the microprocessor via a serial interface The audio from the Bluetooth microphone will be sent to a PCM codec 24 which will output an analog signal that can then be fed into an A to D input on the microcontroller 8 2 Hardware Design Narrative The microcontroller accomplishes many important tasks First it will receive input audio and process that audio to determine if speech is present Second it will interface with the SD card to save and read back audio Third it coordinates the operations of the rest of the components Fourth the microcontroller will be interfacing with the LCD and push buttons to display and change the current settings Finally the microcontroller will be interfacing with the GSM module to turn it on and monitor its status Components will be interfaced via SPI parallel serial as well as some discrete inputs outputs The modules of the microcontroller that will be used are the Timing module PWM SPI Serial UART and the Analog to Digital converter 8 2 1 SPI The SPI subsystem of the microcontroller will be used to communicate with the GSM module and SD card The microcontroller will communicate in slave mode with the GSM module as the master on SPI port 2 on the following pins SS2 SCK2 SDI2 and SDO2 The microcontroller will be the master for communication with the SD card on SPI port 1 utilizing
89. r file of compiler check if OC is in PWM Mode if OC1CONbits OCM amp 0x06 0x06 OC1RS dutycycle assign to OCRS self explanatory void enableATD void _ADLIF 0 EnableIntADCl ADICON1bits ADON 1 return self explanatory void disableATD void _ 0 DisableIntADCl ADICON1bits ADON 0 return debug stuff SCI void printbyte unsigned char val unsigned char nibble unsigned char res build rep of high byte and send nibble val 16 printhexdigit nibble nibble val 16 printhexdigit nibble return makes the non ASCII digit into a hex digit and prints it void printhexdigit unsigned char digit if digit gt 0 amp amp digit lt OxOF have A F digit digit 0x37 else if digit lt 0x09 have 0 9 digit digit 0x30 else F 23 Fall 2006 ECE 477 Final Report Fall 2006 digit 0x30 LCD_put_char digit return void prints char msg char sptr sptr msg while sptr 0 while U1STAbits UTXBF 1 Wait TX buf read for new data UITXREG sptr 5 return SPI2 for GSM unsigned int ReadSPI2 Check for Receive buffer full status bit of status register if SPI2STATbits SPIRBF SPI2STATbits SPIROV 0 if SPI2CON1bits MODE16 return SPI2BUF return word read else return SPI2BUF amp Oxff return b
90. range The DigiSpi will also feature antennas but they will be internal in order to maintain the product s ability to hide its true function 7 4 Project Packaging Specifications When considering the packaging options for the DigiSpi there is one overlying factor that guided the ultimate decision the desire to use the AC power source of a wall outlet Considering this the best option for packaging the product is to hide it in the base of a wooden or ceramic lamp Lamps are common household items found in nearly every room and would serve as a good base station for the DigiSpi hardware 25 ECE 477 Final Report Fall 2006 When designing the specifications for the lamp the only area of interest is the base which will house the PCB LCD and internal antennas for the Wi Fi and GSM modules The base will be 8 in x 10 in x 12 in The 8 in x 10 in base is adequate size when taking into account the initial PCB size estimate of 6 in x 6 in and the 12 in height of the base also gives plenty of room for housing the antennas which must be enclosed in order to mask the device s functionality This will be on the larger end of typical household lamps so some innovative packaging design will needed to make the final product seem decorative The initial dimensions for the lamp shade are 8 in x 10 in x 12 in the height of the shade is arbitrary and the other two dimensions were chosen to match the base however this is not a requirement The lamp
91. return Function for algorithm void Set_Threshold void enableATD take control for the time being while buffer cnt lt 20 if sample flag TRUE sample flag FALSI THRESHOLD temp lt LU lt disableATD set up pointers again in case any sideffects buffer cnt 0 first 1 ISR ptr 0 SD ptr 1 F 12 Fall 2006 ECE 477 Final Report Fall 2006 cnt 0 set the threshold for processing THRESHOLD THRESHOLD 20 return state machine for the main loop enum state typ RESET RUN UPDATE enum state typ curr state SETUP FUNCTION inline void setup void internal setups setup c defined functions setup mem setup GPIO setup timing setup periph Initializes LCD LCD init sets cursor at head of first line LCD_cmd 0x80 LCD_put_string Insert sets cursor at head of second line LCD 0611000000 LCD_put_string SD SD card setup SDSPI SD setStart switches and flags src flag FALSE sample flag FALSE reset flag FALSE err flag FALSE src AID prevRD1 1 prevRD2 1 first 1 ptrs ISR ptr 0 SD ptr 1 cnt 0 Initializes LCD to insert SD screen LCD init LCD cmd 0x80 LCD put string Setting LCD 0611000000 L
92. return 1 while status 0 01 Wait for SD Card to initialize unsigned char CMD1_SEND_OP_COND 0x01 0x00 0x00 0x00 0x00 OxFF i 0 do status SD_WriteCommand CMD1_SEND_OP_COND if it gt 50 return 2 while status amp R1 IN IDLE STATE 0 Send CMD55 required to precede all application specific commands unsigned char CMD55 APP CMD 55 0x00 0x00 0x00 0x00 0xFF status SD WriteCommand CMD55 APP CMD Do not check response her Send the ACMD41 command to initialize SD Card mode not supported by MMC cards i 0 unsigned char ACMD41_SD_SEND_OP_COND 41 0x00 0x00 0x00 0x00 do status SD_WriteCommand ACMD41_SD_SEND_OP_COND Might return 0x04 for Invalid Command if MMC card is connected 1 1 gt 50 return 3 while status amp R1 IN IDLE STATE 0 Set the SPI bus to full speed now that SD Card is initialized in SPI mode SD Disable return 0 this taken from MidiMaestro directly not augmented much void InitSPI void SD PowerOff F 31 ECE 477 Final Report SD_PWR_DIR 0 output SD PowerOff SD Disable SD CS DIR 0 output SD Disable SDI DIR 1 input SCK DIR 1 SDO DIR 1 set SPI port to slowest setting master mode 8 bit Idle state for Clock is high level Primary prescaler 64 1 Sec
93. round planes since SAR successive approximation register A D conversion will be utilized 36 The Ezurio Bluetooth module and WiPort Wi Fi server will only be handling digital signals so they will be grouped in a digital section of the PCB Device placement is also constrained by factors other than noise reduction The SD Memory Card slot will need to be positioned on the edge of the board for access to the spring loaded slot The Bluetooth module has an integrated ceramic antenna To maximize signal propagation it must be placed parallel to the plane of operation 4 Finally headers for the external LCD and pushbuttons will be placed in order to minimize tricky cabling within the packaging Trace size length and routing considerations must be considered in conjunction with part placement and layout As a general rule of thumb traces should be as short and direct as possible to reduce undesirable coupling 36 Also digital parts will be placed closest to board to board and other connectors to prevent interference and signal degradation To further suppress the noise special care will be taken to insure that high frequency signals the audio and clock traces will not be placed close to high impedance input A D input pins on the dsPIC and GM862 GSM cellular modem As per the course recommendation signal traces and spacing will 32 ECE 477 Final Report Fall 2006 be 12 mils but they will be tapered down to 8 mils when approaching the
94. s capacitors 9 4 Summary To accommodate the DigiSpi s diverse set of components a multitude of PCB layout strategies will be used to design a functional and efficient core logic board Digital and analog component separation intelligent trace routing bypass capacitor placement and component mounting techniques will be focused on EMI will also be reduced through the use of a copper ground plane The combination of these steps should result in a reliable device with manageable noise levels 34 ECE 477 Final Report Fall 2006 10 0 Software Design Considerations Figure 10 1 shows the overall block diagram for the dsPIC30F The dsPIC33F used in our final PCB is very similar with the major difference being a larger Data SRAM 64KB in our case From this diagram and the dsPIC30F family overview document it is evident that the Data SRAM and the Flash Program Memory are separate entities allowing an instruction frequency of 33 3MHz and a timer interrupt level of 66 6MHz 31 32 34 The different high frequencies enable the software to function without an external oscillator and to keep a fast processing and interrupt rate 10 1 Code and Memory Setup The Program Memory is Flash programmable and contains sixteen 16 bit registers 31 The most important is the Data SRAM setup due to the importance of buffering data in this project The direct reason for the choice of a dsPIC device was to facilitate DSP instructions if they would be neces
95. sary In our project they were not For the project a C compiler develops the assembly code and many specifics are left to the compiler through macro definitions in the code placed after a variable definition the keyword __attribute_ 33 This will be discussed following the figure X Data Bus 16 06 EEPROM 03 3 Access Program Memory 5 upto 1 144 keen Prefetch amp 1 Legend gt ee 1 6 MCUIOSP Pain ros negate 052 Y Data Pain Adcress Fain Sus 16 0 Figure 10 1 Block Diagram of Microcontroller 31 With respect to the memory many functions were inline to reduce the need for a stack This way the maximum amount of memory is available for buffering and software complexity is greatly reduced The heap is not used instead a general data memory is used for storing flags 35 ECE 477 Final Report Fall 2006 temporary values and buffers loop control variables and pointers Again these will be global reducing the need for specific management in the software The complexity of the memory mapping is further reduced using the C Compiler From Microchip this is the MPLAB C30 Compiler for dsPIC30F and dsPIC33F Families The following table shows where each code and data section is in memory and the preprocessor definitions used for compiler recognition 33 The far means an addressable memory further from the base of th
96. ser Guide Online Document November 2006 accessed January 31 2007 http www telit co it data uploads EN products 1vv0300692 862 QUAD Hardware User Guide r4 pdf SanDisk SD Card Physical Layer Specification Online Document May 2001 http www sandisk com Assets File OEM Manuals SD Physical specsv101 pdf Ezurio BISM2 Bluetooth Version 2 0 Serial Module Online Document unknown publication date accessed January 31 2007 http www ezurio com dl id 88 Hitachi HD44780U LCD II Dot Matrix Liquid Crystal Display Controller Driver Online Document 1999 accessed January 23 2007 http www sparkfun com datasheets LCD HD44780 pdf Microchip dsPIC33F Family Data Sheet Online Document 2007 accessed Jan 23 2007 http ww1 microchip com downloads en DeviceDoc 70165E pdf Linear Technology LT1528 3A Low Dropout Regulator for Microprocessor Applications Online Document 1995 accessed Jan 23 2007 http www linear com pc downloadDocument do jsessionid F59qCKyrESmNZOTWONP6 ijwiS76IRLOd9IO2RcOp75XgkbDKyY m7 108404241 navid H0 C1 C1003 C1040 C105 5 P1048 D1350 Freescale 9512 128 Data Sheet Online Document October 2005 accessed Jan 23 2007 http www freescale com files microcontrollers doc data_sheet MC9S12E128V1 pdf Mitsumi Bluetooth Module WML C40 Class 1 Online Document unknown publication date acce
97. serial terminal that could be used for wireless serial communication Ultimately this was not integrated into our final device as it did not add significant functionality to warrant its inclusion Following the receipt of our PCB I was significantly involved with populating the various components and debugging circuit problems on our board One of these circuit issues proved to be quite significant as it was hindering our ability to accurately sample audio input After the population of our board was complete my focus turned to helping with software development My software contributions include working with Brad on the LCD code debugging issues with our input buffering and SD card writing solved by speeding up SPI clock and restructuring buffer push button setup SD initialization routine debugging caught critical error involving the use of an SD only command on a MMC SPI GSM communication LCD status output and speech processing algorithm integration Overall I am very pleased with my role in this project as I was able to contribute in a variety of roles which gave me a comprehensive understanding of the engineering design process ECE 477 Final Report Appendix B Packaging 4 inches Figure B 1 Front View With Panel Fall 2006 ECE 477 Final Report Fall 2006 Figure B 2 Front View No Panel ECE 477 Final Report Fall 2006 10 75 inches Figure B 3 Side View
98. shorted Unpredictable Observation Low Low Medium bypass capacitors behavior and loss Medium criticality given because causing micro to of functionality of variable functionality operate below 3 3V partial or loss complete Table G 1 Microcontroller and Off Board Peripherals Block A FEMCA ECE 477 Final Report Spring 2006 Failure Failure Mode Possible Causes Failure Effects Method of Criticality Remarks No Detection Bl No audio output PWM software error Inability to use Observation Medium Medium criticality is shorting of LPF PWM output for given because this capacitor debugging feature allows playback purposes of stored audio B2 Push button MAX6817 no longer No longer able to Observation Low Low criticality because malfunction de bounces switch or turn on off no vital components mechanical failure in recording or alter will be damaged and push button software settings recording can still occur B3 No audio input MAX 9812L damage Inability to Observation Medium Medium criticality is or passive component sample audio given because this breakdown short from on board feature is critical to mic primary device function B4 LCD display Software corrupt Current status of Observation Low Low criticality is malfunction LCD micro or poor device will not be awarded because none blank or connection to displayed of main functionality is incorrect headers
99. ssed January 23 2007 http www sparkfun com datasheets Wireless Bluetooth Bluetooth SMD Module pdf 10 N Bedwell Homework 3 Design Constraint Analysis and Component Selection Rationale Online Document September 2006 accessed January 23 2007 http cobweb ecn purdue edu dsml ece477 Webs F06 Grp02 files hw3 doc 11 DPAC Technologies Airborne Embedded Wireless Device Server Module Online Document August 2006 accessed Jan 23 2007 http www dpactech com docs wireless products g ab wireless device server module pd f 41 ECE 477 Final Report Fall 2006 12 XIAMEN OCULAR GDM1602K Basic 16x2 Character LCD Datasheet Online Document unknown publication date accessed January 31 2007 http www sparkfun com datasheets LCD GDM1602K pdf 13 Spytronix com 33hr USB Digital Voice and Phone Recorder Online Document 2007 Jan 27 accessed January 27 2007 http www spy tronix com 33hourphonerecorder html 14 COBY Online CXR55 Voice Activated Cassette Recorder Online Document unknown publication date accessed April 7 2007 http www cobyusa com _en prod_item php item CXR55 amp pcat portaudio amp pscat record er amp pscat2 15 SoftRISC Inc VoIP and Multimedia Software Online Document unknown publication date accessed April 7 2007 http www softrisc com products vad html 16 Keenzo Cisco SPA901 Online Document unknown publicatio
100. uF 0 19 1 0 19 Panasonic Digi Key ECG PCE3806CT ND 68uF 0 34 1 034 Panasonic Digi Key ECG PCE3621CT ND 1000uF 1 89 1 1 89 Panasonic Digi Key ECG PCE4179CT ND 10uF 0 17 2 0 35 Panasonic Digi Key SSG P11532CT ND Red Status LED 0 63 1 0 63 SparkFun 4UCON PRT 08032 Audio Jack 3 5mm 0 95 2 1 90 Digi Key CUI Inc PJ 002A Power Connector 0 38 1 0 38 BC847BW FDICT Digi Key Diodes Inc ND NPN Transistor 0 14 2 028 Digi Key Yageo Corp 311 390ERCT ND 390 ohm 0 08 2 0 16 Digi Key Yageo Corp 311 330ERCT ND 330 ohm 0 08 2 0 16 Digi Key Yageo Corp 311 49 9FRCT ND 50 ohm 0 09 1 0 09 Digi Key Yageo Corp 311 10 0KFRCT ND 10k ohm 0 09 9 0 79 Digi Key Yageo Corp 311 47KERCT ND 47k ohm 0 08 5 0 39 Digi Key Vishay Dale 541 2 20KFCT ND 2 2k ohm 0 05 1 0 05 Digi Key Rohm RHMI 37KFCT ND 1 37k ohm 0 05 1 0 05 Digi Key Rohm RHM137FCT ND 137 ohm 0 05 1 0 05 Digi Key CTS Corp 768 141 R47K ND SIP 13x47K 0 79 1 0 79 Mouser ALPS 688 SKQGAB Surface Mount Push Button 0 71 1 0 71 Radio Momentary Pushbutton Switch2 Shack 275 1556 Pk 2 99 1 2 99 Total Cost for Discrete Components 20 24 Table E 2 Discrete Components E 2 ECE 477 Final Report Fall 2006 Home Depot Unknown N A Wood 12in x 4ft x 1in 8 25 1 8 25 Wal Mart Unknown Unkown Lamp Cord base and socket 9 99 1 9 99 Target
101. ugh came down to the vast possibilities for the integrated DSP functionality of the dsPIC The algorithm for voiced unvoiced speech detection was developed in parallel with the hardware and thus the computation requirements were unknown at the time of microcontroller selection The dsPIC has single cycle multiplies and built in DSP functions that would be more than sufficient for any algorithm developed 6 3 2 2 Bluetooth Module Selection The Ezurio BISM2 was compared to the MITSUMI Bluetooth WML C40 module The two modules provided very similar functionality Both were Bluetooth 2 0 qualified with RS 232 serial interfaces A PCM audio interface is also present on both devices The similarities continue with their integrated ceramic antennas and 300 kbps max data transfer rate 4 9 There are some differentiating qualities though The current draw on the Ezurio model is 30 mA compared to 90 mA for the MITSUMI 4 9 The Ezurio also handles a wider input voltage range 3 3V 6 0V compared to 3 2V 4 0V The BISM2 though costs 99 99 in single unit quantities while the MITSUMI is only 64 95 in the same quantities The deciding factor though was the availability of documentation and support Ezurio s website has easy access to all the necessary technical documentation MITSUMI on the other hand has an English Website that is under construction and individual requests must be made for ECE 477 Final Report Fall 2006 all documentation
102. ustom parts we used Once the PCB was returned I was involved in soldering a few of the easier packages including some electrolytic capacitors as well as a variety of 1206 packages The majority of my soldering however was with headers and connectors for the LCD and SD card In terms of the software I adapted code for a generic LCD to be used with our specific display and created function for the various screen updates including the up time and peripheral status I also was involved in the general debugging and testing of the code I was also responsible for getting familiar with the GSM module and writing the Python code associated with it Finally I was involved in organizing the final documentation specifically editing and stitching together the final report ECE 477 Final Report Fall 2006 A 2 Contributions of Karl Herb I am the only computer engineer on the team so I naturally assumed the role of software and website maintenance Throughout the course of the project I setup the website added new descriptions and on conclusion of the project wrote the descriptions and compiled the pictures for it My initial tasking consisted of filling in where was necessary In addition to brainstorming and proofreading I began to design the power supply I selected parts ordered some samples and attempted to draw a schematic for the power design My design was not used in the final project but a power plug jack I sampled was mounted on the PCB
103. was the motivation behind this project Virtually the entire design process from component selection through future version 2 changes is considered in this document ECE 477 Final Report Fall 2006 1 0 Project Overview and Block Diagram The Digi Spi is an intelligent audio surveillance system that is housed discreetly inside of a lamp Figure 1 1 Photograph of Completed Digi Spi The Digi Spi system has a microphone jack for audio input As audio is captured the Digi Spi makes a determination as to whether the audio contains speech or not If captured audio is determined to contain speech it is stored on an SD card The Digi Spi can be accessed in three ways First a GSM module that allows users to call in and listen live Second the SD card can be removed Finally users can play back the audio and listen through the headphone jack The intended application for the Digi Spi is as a discreet form of home surveillance Parents could place the Digi Spi in a common room and then would be able to call the device to hear live audio or review past speech captured on the SD card This would be especially useful for parents wary of leaving their children alone in the house ECE 477 Final Report Fall 2006 Microphone input 3 3 DC 2 RD4 RD11 RG12 RG14 RDI RD2 SD card dsPIC33FJ256GP710 3 3V DC 3 3V DC 1A Regulators SCK2 SDI2 SDO2 SS2 RB12 RBI3 5VDC 3 8VDC 2A ON RE
104. we managed to design create and package a consumer oriented device With this type of a project a number of different aspects must be considered from software and hardware to safety and reliability This course above all gave us a better appreciation for what all goes into the development of a product Designing and creating a working PCB layout was a major accomplishment As a group our previous experience with this aspect of the design process was very limited Needless to say we learned a lot about taking a schematic and turning it into a usable printed circuit board We learned how to work with new IDE and interfaced with a variety of different peripherals using UART Parallel GPIO and SPI to communicate We also gained a greater appreciation for the engineering design process Throughout the semester our team improved on our project management and team work skills Hardware skills such as creating a schematic and board layout were also acquired Although we did not implement the FAT file system a fair amount was learned about low level memory access on the SD card and how things would likely work if we did implement a file system 40 ECE 477 Final Report Fall 2006 13 0 References 1 2 3 4 5 6 7 8 9 Lantronix WiPort Data Sheet Online Document unknown publication date accessed January 31 2007 http www lantronix com pdf WiPort_DS pdf Telit GM862 QUAD PY Hardware U
105. with the same timing constraints as before This diagram is seen above this paragraph and is the illustration on the right The final mode is an update mode In this mode the and timer 1 interrupts disabled if the src_flag is set and the mode is changed to read from the SD card if it is buffering from the ATD or visa versa If the SD card will be read the buffers are first filled with all the data they can hold before continue Thereafter and timer 1 interrupts are re enabled and the state returns to run with the new mode In order to determine if the block contains voice activity the algorithm computes two values for a given block of audio and compares those values against thresholds The two values are number of zero crossings and average power The number of zero crossings is calculated by multiplying each value by its previous value and adding up the number of those results that are below zero because consecutive positives or consecutive negatives both result in positive values when multiplied The average power of the signal is calculated by summing up the square of each value The threshold for average is set during reset The process consists of measuring the average power for a given period of time and then using a constant offset to scale the threshold slightly above the recorded ambient noise level 10 4 Summary The speech processing algorithm state machine design timer and interrupt driven and the memory layout of
106. y change and spectral change statistics to determine a likelihood of speech Since the Digi Spi uses a much simpler algorithm 13 ECE 477 Final Report Fall 2006 that consists only of comparison to an average energy threshold the detection of speech appears to be done in a substantially different way The second patent analyzed 18 mentions a predictive comparison in addition to the initial threshold comparison This is also significantly different than the energy threshold that the Digi Spi uses to determine which parts of the input audio contain speech The third patent analyzed 19 utilizes frequency band energies to determine if speech is present The Digi Spi does not make any estimation of frequency content and therefore appears to be significantly different from the algorithm described in this patent 4 3 Summary and Action Recommended In terms of the speech detection algorithm there appears to be reasonably low likelihood of any infringement on the patents discussed This is because of the relatively simplistic nature of the algorithm being used compared to the patents discussed Also the amount of prior art involving use of thresholds for detection seems to make any infringement very unlikely Important to note however is that any change in future detection algorithms used by the device could impact this status Two issues make it unlikely that our product will encounter any infringement issues First of all our product will li
107. yte read return 1 RBF bit is not set return error void WriteSPI2 unsigned int data out if SPI2CON1bits MODE16 word write SPI2BUF data out else SPI2BUF data out amp Oxff byte write end setup c F 24 ECE 477 Final Report Fall 2006 SD h SD h Author Karl Herb This code sets up the SD card for I O and reads and writes blocks of 512 bytes to and from the card using an SPI interface This contains the external function definitions A include p33FJ256GP710 h legacy defines define OK 0x00 define PRINT_ERR 0x01 define INIT_ERR 0x02 define SD_ERR 0x03 define the block size as 512 the standard for SD card interface define SD_BLOCK_SIZE 512 external functions for setup reseting to the beginning of the card and 1 0 unsigned char setup_SDSPI void void SD_setStart void unsigned char SD_GetSample int void SD_SetSample int unsigned char void SD_writeCurr void void SD_readCurr void F 25 ECE 477 Final Report Fall 2006 SD c built around functions generated by MpAMModules MidiMaestro SD c Author Karl Herb SD vs MMC card bug fix Justin Lanning This code sets up the SD card for I O and reads and writes blocks of 512 bytes to and from the card using an SPI interface This is developed from the MidiMaestro code and uses much of their original design and defaults NOTE legacy defined in ori

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