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AN731

1. void Menu void Displays menu on user s terminal screen Allows changes to username password phone number and web page void Menu void i 0 CTS 0 enable send while ch 0x1b 2000 Microchip Technology Inc Preliminary DS00731A page 65 AN731 lcd_putc fPC Terminal menu printf c 2J esc printf c 8 25H 1 Enter user name esc printf c 10 25H 2 Enter password esc printf c 12 25H 3 Enter phone number esc printf c 17 30H ESC exit esc ch getc Get input and process switch ch case 0x31 1 gt change username Get_username break case 0x32 2 gt change password Get_password break case 0x33 3 gt change phone Get_phone break CTS 1 disable send Filename F877 H Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 31 00 Compiled using CCS PICC This is a header file containing register and bit definitions for the PIC16F877 External Clock provided by Si2400 modem 9 83
2. Filename LCD_CUT C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 24 00 Compiled using CCS PICC This file contains the LCD interface routines to send a nibble byte initialize the LCD goto an x y coordinate and write a byte External Clock provided by Si2400 modem 9 8304MHz void lcd_send_nibble byte n Writes 4 bits of information to the LCD display void lcd_send_nibble byte n lcd data n Write nibble to port delay_cycles 1 delay lcd enable 1 clock data in delay_us 2 lcd enable 0 AN731 DS00731A page 34 Preliminary 2000 Microchip Technology Inc void lcd_send_byte byte address byte n Writes the byte n to the address in address void lcd_send_byte byte address byte n set_tris_b LCD_WRITE set TRIS bits for output lcd reg_sel 0 delay_us 50 lcd reg_sel ad
3. void Get_phone byte p_tmp printf c 2J esc Print request to terminal printf c 12 20H 16 chars max esc printf c 10 20H Enter phone number esc i 0 while 1 Read characters until a CR is read or 16 chars phone i 0 have been read ch getc if ch 0x0D break if ch 0x0A line feed putc ch if ch 0x08 phone i ch i if i 16 break write phone number to the EEPROM p_tmp 0x40 for i 0 i lt 16 i ch phone i write_ext_eeprom p_tmp phone i p_tmp AN731 DS00731A page 22 Preliminary 2000 Microchip Technology Inc void Read_file void Requests and reads the HTML web page that is sent when requested by a web browser This routine strips out all carriage returns and line feeds found in the file It also lookds for a semi colon to end the file void Read_file printf c 2J esc Print request to the terminal printf c 10 20H Ready to receive file esc printf c 12 20H 32688 bytes max esc printf c 14 20H End file with esc printf c 16 20H Set your terminal for Hardware Flow Control esc ch 1 i 0 index 0x50 while 1 CTS 0 enable send ch getc get characte
4. void temp_config byte data i2c_start Send start bit i2c_write 0x90 Send address byte i2c_write 0xac Send command byte i2c_write data Send data i2c_stop Send stop bit void init_temp void Initializes DS1721 temperature measurement IC using the I2C module void init_temp void output_high PIN_B7 Configure I O pins output_high PIN_B6 i2c_start Send start bit i2c_write 0x90 Send address byte i2c_write 0xee Send command byte i2c_stop Send stop bit temp_config 8 9 bit mode was 8 byte read_temp void Reads the temperature from the DS1721 Value returned is degrees F from 0 to 255 byte read_temp void byte datah datal long data i2c_start Send start bit i2c_write 0x90 Send address byte i2c_write 0xaa Send command byte i2c_start Send start bit restart i2c_write 0x91 Send address byte w read datah i2c_read Read a byte datal i2c_read 0 Read a byte i2c_stop Send stop bit data datah Format received data ctmp data data data 9 if datal amp 0x80 0 data data 4 data data 5 32 datal data return datal Retur
5. void Make_arrow void set_tris_b LCD_WRITE Configure TRIS bits lcd reg_sel 0 Select command registers lcd enable 0 delay_ms 15 lcd_send_byte 0 0x40 send start address lcd reg_sel 1 Select data registers lcd_putc 4 Write arrow data lcd_putc 4 lcd_putc 4 lcd_putc 4 lcd_putc 21 2000 Microchip Technology Inc Preliminary DS00731A page 51 AN731 lcd_putc 14 lcd_putc 4 lcd reg_sel 0 Select command registers lcd_send_byte 0 0x80 void main void void main void Initialize PORTs amp TRISs PORTA 0x24 00100100 PORTB 0xff 00000000 PORTD 0 00000000 PORTE 0xFA 11111010 TRISA 0xE3 11100011 TRISB 0xff TRISC 0x98 10011000 TRISD 0xff 11111111 TRISE 0 00000000 ADCON1 0x06 00000110 all digital to start ADCON0 0 PR2 0x07 Enable amp use PWM CCPR2L 0x03 CCP2CON 0x0C 00001100 T2CON 0x04 00000100 T1CON 0x31 00110001 Timer1 LED1 1 LED OFF LED2 1 CTS 1 disable send Quan_1 QUAN Quan_2 QUAN lcd_init initalize the LCD Make_arrow Create a down arrow in LCD RAM ch bit_test PORTA 1 test for menu button if ch 0 Menu Show enter menu Write_data_to_rs232 This ro
6. void lcd_putc char c Writes the byte c to the current cursor position Routine detects form feeds returns and backspaces void lcd_putc char c switch c case f form feed lcd_send_byte 0 1 delay_ms 2 break case n new line 2000 Microchip Technology Inc Preliminary DS00731A page 61 AN731 lcd_gotoxy 1 2 break case b backspace lcd_send_byte 0 0x10 break default character lcd_send_byte 1 c break Filename INT_EE C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 31 00 Compiled using CCS PICC This file contains the routines to read and write data to the internal EEPROM on the PIC16F877 device void WriteIntEE char Addr char DataPtr char NumBytes This routine writes data to the internal EEPROM on the PIC16F8xx devices It is designed to write 1 byte up to 255 bytes Addr address in EEPROM to begin writi
7. Writes the byte n to the address in address AN731 DS00731A page 60 Preliminary 2000 Microchip Technology Inc void lcd_send_byte byte address byte n set_tris_b LCD_WRITE set TRIS bits for output lcd reg_sel 0 delay_us 50 lcd reg_sel address select register to write delay_cycles 1 lcd rd_w 0 set for writes delay_cycles 1 lcd enable 0 lcd_send_nibble n gt gt 4 write data byte in nibbles lcd_send_nibble n amp 0xf TRISB 0xfd void lcd_init void Initializes the LCD display void lcd_init byte i set_tris_b LCD_WRITE set tris bits lcd reg_sel 0 select configuration lcd enable 0 delay_ms 15 lcd_send_byte 0 0x28 Write config info lcd_send_byte 0 0x0C lcd_send_byte 0 0x01 TRISB 0xfd void lcd_gotoxy byte x byte y Changes the cursor position to x y void lcd_gotoxy byte x byte y byte address if y 1 Check for line 1 or 2 address lcd_line_two else address 0 address x 1 lcd_send_byte 0 0x80 address Write cursor position
8. 3 V R12 10 k 3 V 10 k 3 V 3 V R9 10 k MCLR MENU CALL LEFT 4 3 2 1 S5 RC4 RIGHT RA0 RIGHT LEFT 10 k R11 R10 R13 470 R14 470 R15 470 R16 470 R17 470 AN731 DS00731A page 42 Preliminary 2000 Microchip Technology Inc FIGURE D 2 TCP IP CLIENT SODA MACHINE SHEET 2 OF 3 3 V TXD 1 RESET 2 TEST 3 CLK 4 VSS 5 CTSX 6 DSRX 7 RI 8 RXD 9 DCD 10 DTRX 11 DTSX 12 TXD 36 BUSYX 35 INT2X 34 INT1 33 INTCTRL 32 WRITEX 31 PSX 30 VSS 29 READX 28 C86 27 CS 26 RS 25 T13 U2 S 7600A 1 QL 15 QK 14 QJ 12 QI 13 QH 4 QG 2 QF 3 QE 5 QD 6 QC 7 QB 9 QA 10 CLK 11 CLR U8 SN74HC4040DW OSC1 CLK1 CLK 1 2 3 J1 SIP_3 CLK RESET RXD 1 F C1 DCD BUSYX WRITEX READX RS CS 3 V 3 V INT1 C5 1 F 1 F C12 3 V for U8 SD0 SD1 SD2 SD3 SD4 SD5 VDD TI1 TI2 NC SD7 SD6 SD0 SD1 SD2 SD3 SD4 SD5 SD6 SD7 48 47 46 45 44 43 42 41 40 39 38 37 T07 T06 T05 T04 T03 T02 T01 VDD T17 T16 T15 T14 13 14 15 16 17 18 19 20 21 22 23 24 2000 Microchip Technology Inc Preliminary DS00731A page 43
9. the S 7600A Returns the value of the data available bit from the S 7600A char DataAvailable void return ReadSeiko Serial_Port_Config amp 0x80 void S_Putc char data Writes a byte of data to the serial port on the S 7600A void S_Putc char data while BUSY Check if S 7600A is busy CS 1 1st cycle sets register RS 0 address WRITEX 0 PORTD Serial_Port_Data Write to serial port TRISD 0 READX 1 READX 0 WRITEX 1 RS 1 CS 0 CS 1 2nd cycle writes the data WRITEX 0 to the register PORTD data Data to write READX 1 READX 0 WRITEX 1 CS 0 TRISD 0xff void W_Putc char data Writes a byte of data to the socket on the S 7600A void W_Putc char data 2000 Microchip Technology Inc Preliminary DS00731A page 59 AN731 Make sure that the socket buffer is not full while 0x20 ReadSeiko 0x22 amp 0x20 WriteSeiko TCP_Data_Send 0 If full send data while ReadSeiko Socket_Status_H Wait until done while BUSY Check if S 7600A is busy CS 1 1st cycle sets reg
10. 2000 Microchip Technology Inc Preliminary DS00731A page 1 AN731 INTRODUCTION The market for products or services that are Internet related is HOT Increased amounts of money and design resources are being thrown at these products and services One significant portion of this trend is to embed the Internet or in other words make embedded products have the capability to connect to the Internet It is estimated that by the year 2005 the number of embedded applications with the ability to connect to the Internet will be larger than the number of PCs by a fac tor of 100 or more The latest in PDAs and cellular telephones allow the user to access stock quotes sports scores E mail and more The other advantage of the movement to embed the Internet is enabling client devices such as appli ances and vending machines to connect to the Internet and upload status information The price for such prod ucts is being reduced dramatically due to the introduc tion of new technology The application note presented here is based on the block diagram shown in Figure 1 It consists of the PIC16F87X microcontroller the Seiko iChipTM S 7600A TCP IP stack IC and the ISOmodemTM Si2400 and Si3015 DAA from Silicon Labs Each of these components was specifically selected for this application because of the feature set it provides Each of the following sections will present the reasons for selection The sample applications include both
11. RFC959 FTP RFC792 ICMP RFC791 IP RFC768 UDP Internetworking with TCP IP Prentice Hall 1995 Douglas E Comer AN731 DS00731A page 10 Preliminary 2000 Microchip Technology Inc APPENDIX A GLOSSARY ARP Address Resolution Protocol The TCP IP protocol that translates an Internet address into the hardware address of the network interface hardware client A program that requests services from a server client server A style of computing that allows work to be distributed across hosts DNS Domain Name System The name address resolution service that uses a distributed database containing address DNS makes it easier to refer to computers by name rather than numeric address www microchip com instead of 198 175 253 68 FTP File Transfer Protocol A TCP IP application service and protocol for copying files from one computer to another HTML HyperText Markup Language The language used to write pages for the Internet HTTP HyperText Transfer Protocol The TCP IP protocol for transferring pages across the Internet ICMP Internet Control Message Protocol The TCP IP protocol used to report network errors and to determine whether a computer is available on the network Internet The international collection of inter nets that use TCP IP to work together as one immense logical network IP One of the two main parts of the TCP IP protocol suite IP delivers TCP and UDP pack
12. THIS SOFTWARE IS PROVIDED IN AN AS IS CONDITION NO WARRANTIES WHETHER EXPRESS IMPLIED OR STATU TORY INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICU LAR PURPOSE APPLY TO THIS SOFTWARE THE COMPANY SHALL NOT IN ANY CIRCUMSTANCES BE LIABLE FOR SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR ANY REASON WHATSOEVER APPENDIX C EMBEDDED WEB SERVER SOURCE CODE Filename MODEM_C C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 24 00 Compiled using CCS PICC Include files 16f877 h f877 h s7600 h ctype h string h lcd_cut c seiko_ct c eeprom c This program demonstrates a simple WEB severer using a Microchip PIC16C74B microcontroller and a Seiko S 7600 TCP IP Network Protocol chip This is the main file that includes all other header files and source code files External Clock provided by Si2400 modem 9 8304MHz include lt 16c77 h gt include f877 h include s7600 h include lt ctype h gt in
13. Write the port address WriteSeiko Their_Port_L PORT_L for both the server WriteSeiko Our_Port_H PORT_H and the client WriteSeiko Their_Port_H PORT_H WriteSeiko Socket_Config_Status_L 0x02 Use TCP client mode WriteSeiko Socket_Activate 0x01 Activate socket Loop to wait for socket to be connected with the server while 1 delay_ms 5 j ReadSeiko Socket_Status_M if j amp 0x10 i 0 break else if j amp 0xe0 break 2000 Microchip Technology Inc Preliminary DS00731A page 55 AN731 CONNECTED 1 The client must respond with the current index into the array to get the next set of item names and prices Use Item_Number where Item_Number is between 0 and 9 Item_Num Increment item number if Item_Num gt 9 Check for overflow Item_Num 0 WriteSeiko Socket_Data Write the string to the S 7600A WriteSeiko Socket_Data WriteSeiko Socket_Data Item_Num WriteSeiko Socket_Data WriteSeiko Socket_Data WriteSeiko Socket_Data 0X0A WriteSeiko Socket_Data 0X0D WriteSeiko TCP_Data_Send 0 send data LED2 1 turn LED2 OFF Server should respond with data that has the following sequence lt Item1 gt lt Item2 gt lt Price1 gt lt Price2 gt These are strings that have names and prices lcd_putc fReading Data while ReadSeiko Socket_Config_Status_L amp 0x10 temp ReadS
14. 2000 Microchip Technology Inc char ReadSeiko char address Reads a byte of data from a register on the S 7600A char ReadSeiko char address char data while BUSY Wait for S 7600A CS 1 1st cycle sets register address RS 0 WRITEX 0 PORTD address Write address TRISD 0 READX 1 READX 0 WRITEX 1 RS 1 CS 0 TRISD 0xff 2nd cycle CS 1 RS 0 READX 1 data PORTD READX 0 RS 1 CS 0 while BUSY Wait for S 7600A CS 1 to get data READX 1 data PORTD Read data READX 0 CS 0 return data Filename EEPROM C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 24 00 Compiled using CCS PICC This file contains external EEPROM access routines Initialization write and read routines are provided External Clock provided by Si2400 modem 9 8304MHz void init_ext_eepr
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16. Modem PC Card 2000 Microchip Technology Inc Preliminary DS00731A page 7 AN731 FIGURE 4 ISOcap INTERFACE WEB SERVER APPLICATION The embedded web server application is more for show and tell As mentioned before it is not really a practical use of the hardware The memory sizes required to serve web pages and data files far outweighs that which can be found on a typical microcontroller In fact if the price of non volatile semiconductor memory and that of hard drives were compared the results would show that the average price per megabyte of FLASH memory is approximately 1 00 2 00 and approxi mately 0 01 0 05 for hard drives That equates to a ratio of 40 1 favoring hard drives Demonstrations of embedded web servers are just that demonstrations of Internet connectivity They are easy to design and require nothing more than a web browser and a phone line to demonstrate the capabili ties Demonstrating a client application such as a vend ing machine is more difficult Toting around a vending machine in your car for product demonstrations really impacts your gas mileage It s heavy too Appendix B shows the schematic for the embedded web server It uses the PIC16F877 the S 7600A TCP IP stack IC the Si2400 modem and Si3015 DAA The design uses 24LCxx serial EEPROM that comes in sizes from 16 bytes up to 32 Kbytes It holds the ISP phone number user name and password and the HTML web page Also in
17. RS 1 CS 0 CS 1 2nd cycle writes the data WRITEX 0 to the register PORTD data Data to write READX 1 READX 0 WRITEX 1 CS 0 TRISD 0xff void W_Putc char data Writes a byte of data to the socket on the S 7600A void W_Putc char data Make sure that the socket buffer is not full while 0x20 ReadSeiko 0x22 amp 0x20 WriteSeiko TCP_Data_Send 0 If full send data while ReadSeiko Socket_Status_H Wait until done while BUSY Check if S 7600A is busy CS 1 1st cycle sets register RS 0 address WRITEX 0 PORTD Socket_Data Write to socket TRISD 0 READX 1 READX 0 WRITEX 1 RS 1 CS 0 AN731 DS00731A page 20 Preliminary 2000 Microchip Technology Inc CS 1 2nd writes the data to WRITEX 0 the register PORTD data Data to write READX 1 READX 0 WRITEX 1 CS 0 TRISD 0xff include eeprom c external serial EEPROM routines void Get_username void Requests and reads the user name from the input terminal void Get_username void char n_tmp i 0 printf c 2J esc Print request to term
18. bit SSPM0 SSPCON 0 CCP1CON Bits bit CCP1X CCP1CON 5 bit CCP1Y CCP1CON 4 bit CCP1M3 CCP1CON 3 bit CCP1M2 CCP1CON 2 bit CCP1M1 CCP1CON 1 bit CCP1M0 CCP1CON 0 RCSTA Bits bit SPEN RCSTA 7 bit RX9 RCSTA 6 bit SREN RCSTA 5 bit CREN RCSTA 4 bit ADDEN RCSTA 3 bit FERR RCSTA 2 bit OERR RCSTA 1 bit RX9D RCSTA 0 CCP2CON Bits bit CCP2X CCP2CON 5 AN731 DS00731A page 68 Preliminary 2000 Microchip Technology Inc bit CCP2Y CCP2CON 4 bit CCP2M3 CCP2CON 3 bit CCP2M2 CCP2CON 2 bit CCP2M1 CCP2CON 1 bit CCP2M0 CCP2CON 0 ADCON0 Bits bit ADCS1 ADCON0 7 bit ADCS0 ADCON0 6 bit CHS2 ADCON0 5 bit CHS1 ADCON0 4 bit CHS0 ADCON0 3 bit GO ADCON0 2 bit NOT_DONE ADCON0 2 bit CHS3 ADCON0 1 bit ADON ADCON0 0 OPTION Bits bit NOT_RBPU OPTION_REG 7 bit INTEDG OPTION_REG 6 bit T0CS OPTION_REG 5 bit T0SE OPTION_REG 4 bit PSA OPTION_REG 3 bit PS2 OPTION_REG 2 bit PS1 OPTION_REG 1 bit PS0 OPTION_REG 0 TRISE Bits bit IBF TRISE 7 bit OBF TRISE 6 bit IBOV TRISE 5 bi
19. to PAP register ch read_ext_eeprom j WriteSeiko PAP_String ch WriteSeiko PAP_String 0x00 Write NULL to PAP register printf S_Putc ATDT ch 1 Read phone out of EEPROM amp write to modem index 0x40 beginning of phone number in EEPROM while 1 ch read_ext_eeprom index if ch 0 end of string break S_Putc ch index 2000 Microchip Technology Inc Preliminary DS00731A page 27 AN731 printf S_Putc r end with CR LF delay_ms 5 printf c 2J esc clear VT100 screen lcd_putc fCall n Print message that modem printf rDialing is dialing ch 1 Write phone to LCD and terminal i 0x40 beginning of phone number in EEPROM while 1 ch read_ext_eeprom i if ch 0 end of string break printf c ch write number to RS 232Terminal printf lcd_putc c ch write number to LCD display i printf r send with CR LF Read status bytes from modem will dialing while 1 i ReadSeiko Serial_Port_Config Read UART status lcd_send_byte 0 0x87 goto first line char 8 if bit_test i 7 If data available ch ReadSeiko Serial_Port_Data read if ch t dial tone detected lcd_putc dial tone n printf ndial tone r if ch r ring detected lcd_putc ring printf nring r if ch c modem connected bre
20. 31 RD5 32 RD6 33 RD7 11 RE2 10 RE1 9 RE0 12 VDD U1 PIC16F877 RB6 RB7 R9 10 k MCLR RA1 RB5 4 3 2 1 S1 4 3 2 1 S2 CTS OSC1 CLK1 SCL SDA RB4 RB3 RB2 R8 300 R5 300 SD6 RA3 RS CS WRITEX READX SD5 SD4 SD3 SD2 RB1 RESET BUSYX SD0 SD7 SD1 RXD2 TXD2 MCLR R1 10 k 1 F C4 3 V C2 1 F 3 V C3 1 F 3 V D1 D2 R4 10 k 3 V 3 V RA1 INT1 4 GND 1 A0 2 A1 3 A2 5 SDA 6 SCL 7 WP 8 VCC U4 24LC08B_DIP 4 7 k R6 R7 4 7 k SCL SDA 3 V 1 F C11 SDA SCL 3 V RB6 RB7 MCLR 1 2 3 4 6 5 JP2 RJ11_6PIN 3 V 4 GND 8 VCC 1 SDA 2 SCL 3 Tout 7 A0 6 A1 5 A2 U7 DS1721_SO8 1 F C10 R10 470 R11 470 AN731 DS00731A page 12 Preliminary 2000 Microchip Technology Inc FIGURE B 2 TCP IP SERVER MODEM SHEET 2 OF 3 3 V TXD 1 RESET 2 TEST 3 CLK 4 VSS 5 CTSX 6 DSRX 7 RI 8 RXD 9 DCD 10 DTRX 11 DTSX 12 TXD 36 BUSYX 35 INT2X 34 INT1 33 INTCTRL 32 WRITEX 31 PSX 30 VSS 29 READX 28 C86 27 CS 26 RS 25 T13 U2 S 7600A 1 QL 15 QK 14 QJ 12 QI 13 QH 4 QG 2 QF 3 QE 5 QD 6 QC 7 QB 9 QA 10 CL
21. ITEM 1 BUTTON PRESSED ITEM 2 BUTTON PRESSED AND PRICES 2000 Microchip Technology Inc Preliminary DS00731A page 45 AN731 FIGURE D 5 WEB CLIENT FLOWCHART SHEET 2 OF 3 B WRITE SERVER NO NO YES SOCKET IDLE CLOSE SOCKET ADDRESS TO S 7600A ENABLE SOCKET USE HTML PORT 80 TCP SERVER NO YES SOCKET OPEN TO SERVER SEND INDEX NUMBER YES DATA AVAILABLE READ BYTE FROM S 7600A NO YES CHAR READ IN NEW ITEM NAMES AND PRICES HANG UP MODEM BY RESETTING WAIT FOR USER TO RESET PIC16F877 AN731 DS00731A page 46 Preliminary 2000 Microchip Technology Inc FIGURE D 6 WEB CLIENT FLOWCHART SHEET 1 OF 3 A PRINT MENU SELECTIONS READ CHARACTER 0X31 0X32 0X33 ESC RETURN TO A IN SHEET 1 READ USER NAME AND STORE IN EEPROM READ PASSWORD AND STORE IN EEPROM READ PHONE NUMBER AND STORE IN EEPROM YES NO YES YES YES NO NO NO 2000 Microchip Technology Inc Preliminary DS00731A page 47 AN731 Software License Agreement The software supplied herewith by Microchip Technology Incorporated the Company for its PICmicro Microcontroller is intended and supplied to you the Company s customer for use solely and exclusively on Microchip PICmicro Microcontroller prod ucts The software is owned by the Company and or its supplier and is protected under applicable copyright
22. define lcd_line_two 0x40 LCD RAM address for the second line char Flags Flag register bit CONNECTED Flags 0 Established TCP IP connection bit INTRUSION Flags 1 Parallel phone detect bit WRITEREADING Flags 2 Write count to serial EEPROM bit SECONDS Flags 3 60 second flag bit UPLOAD Flags 4 Make TCP IP connection and upload bit ONHOOK Flags 5 Parallel Phone Detect bit WRITETS Flags 6 bit ATTEMPT Flags 7 byte lcd_cmd cmd_tmp byte CONST LCD_INIT_STRING 4 0x20 lcd_type lt lt 2 0xc 1 6 These bytes need to be sent to the LCD to start it up PORTC bits bit CTS PORTC 0 When CTS 0 send is enabled bit LED1 PORTC 2 When LED 0 the LED is ON bit LED2 PORTC 5 When LED 0 the LED is ON PORTE bits bit READX PORTE 0 bit WRITEX PORTE 1 bit CS PORTE 2 Buttons bit Call PORTA 0 bit T_Menu PORTA 1 bit Left PORTC 3 bit Right PORTC 4 char i j ch addr temp count count1 page long index byt_cnt char MyIPAddr 4 char TheirIPAddr 4 2000 Microchip Technology Inc Preliminary DS00731A page 49 AN731 char user 33 char pass 33 char phone 17 vending machine variables char Item_1 9 char Item_2 9 char Price_1 5 Price_2 5 int Quan_1 Quan_2 Item_Num struct lcd_pin_map This structure is overlayed boolean unused on to an I O port to gain boolean enable access to the L
23. infrastructure is zero and therefore makes the most sense for the bulk of embedded applications There will be applications where the other mediums are needed but the application will be able to justify and therefore absorb the additional costs associated with using the respective mediums Usually the telephone modem technology is signifi cantly less expensive than that of other mediums It also fits better into embedded applications due to size and power consumption The key to modem selection is to find one that is highly integrated i e smaller in size This is important due to the fact that most embed ded applications are small This modem should be easy to use and provide all the necessary features in a single package Fortunately the folks at Silicon Labora tories have developed an embedded modem that may be one of the best designs ever to hit the streets The first feature that stands out is the size Figure 3 shows the size of the Silicon Labs design compared to a stan dard modem design NO relays NO optoisolators NO transformers This design has the Si2400 modem and the Si3015 DAA chip and some passive devices resis tors capacitors diodes and transistors The secret is in the ISOcapTM Technology used to transfer control and data over a capacitive interface as shown in Figure 4 This interface provides a low cost solution based off standard high voltage capacitors and over 2400 V of isolation The cost to implement thi
24. inserts escape characters to distinguish data bytes from flag bytes It also configures the link between the two peers including compression and maximum receive units MRUs Finally it configures the network connection allowing multiple network protocols and negotiation of an IP address PPP does not specify a server or a client It assumes there are two peers both of which have equivalent authority in the connection PPP also handles user name and password authenti cation Two protocols are supported Password Authentication Protocol PAP and Challenge Hand shake Authentication Protocol CHAP Once the link parameters are negotiated PPP is used to transfer data packets between the two hosts and terminate the connection once all the data has been sent The transport layer provides the basic communication between a server and a client User Datagram Protocol UDP is not based on making connections between the hosts In other words the host receiving a packet from another host does not acknowledge the reception Therefore the transmitting host has no indication of whether the packet made it to its destination The acknowledgment can be a return UDP packet from the receiving host However this is not included in the UDP specification and requires additional overhead for both hosts UDP is the best protocol for use when transmit ting small amounts of data or for regular transmissions of small data packets Each UDP packet is encapsu
25. other end to time out in order to recognize that the connection was terminated Rather than implement a software protocol stack that has these type of limitations the designer may choose to use an external TCP IP stack device This device 2000 Microchip Technology Inc Preliminary DS00731A page 5 AN731 should relieve the designer of working around limita tions and allowing more capabilities to be built into the product The TCP IP stack device should minimally implement the Network Access Layer Internet Layer and the Transport Layer as shown in Figure 2 freeing up program memory to implement protocols for the Application Layer A minimal software implementation of the Point to Point Protocol PPP Internet Protocol IP ICMP and UDP TCP would require approximately 5 Kbytes of program memory and at least 4 Kbytes of data memory The now vacant program memory could be used for Simple Mail Transfer Protocol SMTP Post Office Protocol version 3 POP3 or Hyper Text Trans fer Protocol HTTP The S 7600A TCP IP Stack IC from Seiko Instruments was designed specifically for this type of market It inte grates the TCP IP Stack engine 10 Kbytes of RAM microcontroller interface and UART into a single chip Once configured it acts like a data buffer Data to be transmitted up to 1024 bytes is stored in the internal RAM buffer and the TCP IP engine appends the vari ous headers and checksums It then transmits this packet f
26. struct lcd_pin_map This structure is overlayed boolean unused on to an I O port to gain boolean enable access to the LCD pins boolean rd_w The bits are allocated from boolean reg_sel low order up UNUSED will int data 4 be pin B0 lcd byte lcd 6 This puts the entire structure on to port B at address 6 STRUCT lcd_pin_map const LCD_WRITE 1 0 0 0 0 For write mode all pins are out except RB0 int1 include lcd_cut c LCD routines include seiko_ct c Seiko routines 2000 Microchip Technology Inc Preliminary DS00731A page 19 AN731 char DataAvailable void Determines if there is any data available to read out of the S 7600A Returns the value of the data available bit from the S 7600A char DataAvailable void return ReadSeiko Serial_Port_Config amp 0x80 void S_Putc char data Writes a byte of data to the serial port on the S 7600A void S_Putc char data while BUSY Check if S 7600A is busy CS 1 1st cycle sets register RS 0 address WRITEX 0 PORTD Serial_Port_Data Write to serial port TRISD 0 READX 1 READX 0 WRITEX 1
27. 1 Drill holes through the traces from U3 pins 24 and 25 and remove residual traces 2 Cut the copper away from the holes on the bot tom 3 Cut the traces on the bottom of the board going to JP3 pins 5 and 7 4 Lift U1 pin 7 5 Connect a jumper wire from U3 pin 24 through hole to JP3 pin 7 6 Connect a jumper wire from U3 pin 25 through hole to JP3 pin 5 7 Remove shorting jumpers from JPIO 1 and 3 and JP4 The controller board is then bolted directly on top of the evaluation board and makes the necessary connec tions from the S 7600A to the modem the modem to the microcontroller and the microcontroller to the RS 232 interface IC 2000 Microchip Technology Inc Preliminary DS00731A page 9 AN731 CLIENT APPLICATION This application represents a typical embedded Inter net application where the embedded device is the cli ent and is capable of connecting to a server to upload information and download new information or firm ware In this case a vending machine that receives new information The vending machine application has an LCD display that shows the current items in the machine and the price for each It will dispense items until the machine is empty At any time a push button switch may be pressed to start the connection to the server via the Internet The modem dials an ISP makes a connection to the server and receives new names and prices of items to be dispensed The hardware design is a subset
28. 7 Y2 9 Y1 17 A4 15 A3 13 A2 11 A1 19 OE U5 B 74LVTH240 12 Y4 14 Y3 16 Y2 18 Y1 8 A4 6 A3 4 A2 2 A1 1 OE U5 A 74LVTH240 AN731 DS00731A page 14 Preliminary 2000 Microchip Technology Inc FIGURE B 4 WEB SERVER FLOWCHART SHEET 1 OF 3 A B C D B START CONFIGURE PIC16F877 SERIAL E2 AND TEMP SENSOR MENU BUTTON PRESSED YES NO RESET MODEM AND S 7600A CONFIGURE MODEM AND S 7600A PPP AND MODEM STILL CONNECTED ENABLE SOCKET USE HTML PORT 80 TCP SERVER RESET AND ENABLE PPP READ USER NAME PASSWORD AND WRITE TO PAP REGISTER READ PHONE NUMBER AND SEND TO MODEM TO DIAL DETECT BUSY OR NO LINE OR CARRIER YES NO CONNECT YES NO ENABLE PAP RELEASE CONTROL OF UART TO S 7600A NO YES IP ADDRESS CHANGE READ AND DISPLAY IP ADDRESS SOCKET OPEN PPP AND MODEM STILL CONNECTED NO NO YES NO YES NO YES YES DATA RECEIVED AND TEMPERATURE POTENTIOMETER READ 2000 Microchip Technology Inc Preliminary DS00731A page 15 AN731 FIGURE B 5 WEB SERVER FLOWCHART SHEET 2 OF 3 C D READ BYTE FROM SERIAL E2 YES NO CHAR 0 a c f h p WRITE IP ADDRESS TO S 7600A WRITE TEMPERATURE IN CELSIUS TO S 7600A WRITE TEMPERATURE IN FARENHEIT TO S 7600A WRITE NUMBER OF HITS TO S 7600A WRITE POTENTIOMETER VALUE TO
29. LED1 1 LED OFF AN731 DS00731A page 54 Preliminary 2000 Microchip Technology Inc while 1 if ch N No carrier detected gotorestart ch 0 lcd_putc fConnect printf nConnect r LED2 0 turn connected LED2 ON WriteSeiko PPP_Control_Status 0x62 Use PAP enable PPP WriteSeiko Serial_Port_Config 0x01 turn serial port over to S 7600 delay_ms 5 Register 0x60 wait for PPP to be Up while ReadSeiko PPP_Control_Status amp 0x01 delay_ms 5 while ReadSeiko Our_IP_Address_L 0 detect when ready to proceed MyIPAddr 0 ReadSeiko Our_IP_Address_L Read our assigned IP address MyIPAddr 1 ReadSeiko Our_IP_Address_M MyIPAddr 2 ReadSeiko Our_IP_Address_H MyIPAddr 3 ReadSeiko Our_IP_Address_U Print address to the terminal and LCD printf r nMy address is u u u u MyIPAddr 3 MyIPAddr 2 MyIPAddr 1 MyIPAddr 0 lcd_putc fMy address is n printf lcd_putc u u u u MyIPAddr 3 MyIPAddr 2 MyIPAddr 1 MyIPAddr 0 Write the preconfigured server IP address to the S 7600A WriteSeiko T_Address_1 TheirIPAddr 0 WriteSeiko T_Address_2 TheirIPAddr 1 WriteSeiko T_Address_3 TheirIPAddr 2 WriteSeiko t_Address_4 TheirIPAddr 3 for temp 0 temp lt 3 temp WriteSeiko Socket_Index 0x00 Use Socket 0 WriteSeiko Socket_Config_Status_L 0x10 Reset socket delay_ms 5 WriteSeiko Our_Port_L PORT_L
30. Modem delay_ms 10000 Set clock divider for 1KHz clock WriteSeiko Clock_Div_L 0x32 while ReadSeiko Clock_Div_L 0x32 Detects when WriteSeiko Clock_Div_L 0x32 reset done WriteSeiko Clock_Div_H 0x01 AN731 DS00731A page 26 Preliminary 2000 Microchip Technology Inc Set Baud Rate Divisor for 2400 baud 9 828606 WriteSeiko BAUD_Rate_Div_L 0x7e WriteSeiko BAUD_Rate_Div_H 0x00 Set up MODEM printf S_Putc ATS07 06SE2 C0 r Send V22bis to modem delay_ms 10 printf S_Putc ATE0 r Send Local echo off delay_ms 10 WriteSeiko PPP_Control_Status 0x01 enable PPP WriteSeiko PPP_Control_Status 0x00 disable PPP WriteSeiko PPP_Control_Status 0x20 set PAP mode delay_ms 5 Determine length of Username and write it to the PAP register in the S 7600A ch 1 i 0 Beginning of Username string in EEPROM while ch Read until a NULL is reached ch read_ext_eeprom i i i WriteSeiko PAP_String i Write of chars in username for j 0 j lt i j Write Username to PAP register ch read_ext_eeprom j WriteSeiko PAP_String ch Determine length of Password and write it to the PAP register ch 1 i 0x20 Beginning of Password string in EEPROM while ch ch read_ext_eeprom i i i i i 0x20 WriteSeiko PAP_String i Write of chars in password for j 0x20 j lt i 0x20 j Write Password
31. S 7600A WRITE VALUE TO S 7600A IS BUFFER FULL BUFFER EMPTY SEND S 7600A BUFFER YES NO NO YES YES YES YES YES YES NO NO NO NO NO YES NO NO YES SOCKET IDLE CLOSE SOCKET BUFFER EMPTY SEND S 7600A BUFFER AN731 DS00731A page 16 Preliminary 2000 Microchip Technology Inc FIGURE B 6 WEB SERVER FLOWCHART SHEET 3 OF 3 A PRINT MENU SELECTIONS READ CHARACTER 0X31 0X32 0X33 0X34 ESC RETURN TO A IN SHEET 1 READ USERNAME AND STORE IN SERIAL E2 READ PASSWORD AND STORE IN SERIAL E2 READ PHONE NUMBER AND STORE IN SERIAL E2 READ NEW WEB PAGE AND STORE IN SERIAL E2 YES NO YES YES YES YES NO NO NO NO 2000 Microchip Technology Inc Preliminary DS00731A page 17 AN731 Software License Agreement The software supplied herewith by Microchip Technology Incorporated the Company for its PICmicro Microcontroller is intended and supplied to you the Company s customer for use solely and exclusively on Microchip PICmicro Microcontroller prod ucts The software is owned by the Company and or its supplier and is protected under applicable copyright laws All rights are reserved Any use in violation of the foregoing restrictions may subject the user to criminal sanctions under applicable laws as well as to civil liability for the breach of the terms and conditions of this license
32. flow con trol otherwise the USART buffer will be overrun due to the programming time required by the serial EEPROM The application provides lots of status information Messages are displayed when a call is being made a dial tone is detected a ring occurs a busy phone line is detected or when the modem finally makes a con nection The display will show the IP address once the modem has made the connection There are also a couple of LEDs that indicate the status of the web server The first LED shows if the modem is connected The second LED flickers when the web server is being accessed Special characters are used to allow the web server to insert variable data into the web page The following information can be displayed when these characters are found in the HTML web page a displays the IP address for web page reload function c inserts the current temperature in degrees Celsius f inserts the current temperature in degrees Fahrenheit h displays the number of times the web site has been accessed p inserts the current value of the potentiometer Several modifications had to be made to the modem evaluation board It was originally designed to interface the serial port on the PC directly to the modem Using a terminal program the user could make or receive phone calls This interface was hacked to allow stack ing of the control board on top of the modem evaluation board These modifications include
33. httpd 0 9 WriteSeiko Socket_Data 0X0A WriteSeiko Socket_Data 0X0D WriteSeiko Socket_Data 0X0A WriteSeiko Socket_Data 0X0D Send the main HTML page LED2 0 LED2 ON hits increment web site hits set_adc_channel 1 Read potentiometer pot read_adc ftmp read_temp Read temperature Dump web page in EEPROM to S 7600A parse data to insert hits temperature IP address potentiometer value etc byt_cnt 0 index 0x50 beginning of html in EEPROM ch 1 while ch 0 break on NULL ch read_ext_eeprom index Read a byte if ch 0 If NULL quit break if ch 0x25 look for replaceable paramaters LED2 1 toggle LED to indicate activity index ch read_ext_eeprom index get the next char switch ch case a address printf W_putc u u u u MyIPAddr 3 MyIPAddr 2 MyIPAddr 1 MyI PAddr 0 break case c temperature C printf W_putc u ctmp break case f temperature F printf W_putc u ftmp break case h of hits printf W_putc lu hits break case p potentiometer AN731 DS00731A page 30 Preliminary 2000 Microchip Technology Inc printf W_putc 03u pot break else data not replaceable send to S 7600A count 0 count1 0 bit_clear PIR1 TMR1IF clear interrupt flag If buffer is full while 0x20 ReadSeiko 0x22 amp 0x20 Send curren
34. of the web server application Appendix D shows the schematic for the client application This design removes the serial EEPROM potentiometer and temperature IC It adds some push button switches for the additional user interface required It uses the same modem evaluation board as the web server with all the same modifica tions The source code and flowchart for the client is given in Appendix E This source code was also written using the CCS C Compiler The vending machine has two modes of operation It has the standard operating mode of reading the push button switches and dis pensing items based on which button is pressed It tracks the number of items remaining in the vending machine and the total amount of money collected The second mode of operation is the Internet connection Most of the code to interface with the S 7600A is the same as the web server with the exception that it is now a TCP client instead of a TCP web server It must also know what the IP address and port number of the server is before it can make a connection to the server This means that more than a web browser is required to complete the connection on the server side There must be a program running on the server that listens to a port Once connected the transfer of information may take place between the client and the server In this application the Internet connection provides the names and prices of new items Every connection to the server downl
35. reprogrammed not only include the instructions but also sensor calibration tables IDs and application lookup tables For instance the pricing for the vending machine items may be stored in a lookup table that can be reprogrammed by the server when a connection is made When choosing a FLASH based microcontroller it is important to select one with the features that can facil itate this type of remote reprogramming operations The microcontroller must be able to modify its own firm ware without the need for external circuitry It must also have the capability to reprogram without interrupting the operation of the application In other words the peripherals and internal clocks must continue to oper ate and queue events while the microcontroller is reprogramming memory locations One example of this type of microcontroller is the PIC16F87X family of products from Microchip Technol ogy Table 1 shows the current family of products These products provide a migration path for memory size and feature set within a given footprint 28 or 40 pins DNS FTP HTTP UDP TCP PPP ETHERNET ICMP IP 2000 Microchip Technology Inc Preliminary DS00731A page 3 AN731 TABLE 1 PIC16F87X PRODUCT FAMILY These devices have the standard complement of peripherals including USARTs Master Mode I2CTM SPITM A D Capture Compare PWM and Timers It also has up to 8K words of FLASH program memory up to 368 bytes of RAM and 256 byt
36. 04MHz Registers byte INDF 0x000 byte TMR0 0x001 byte PCL 0x002 byte STATUS 0x003 byte FSR 0x004 byte PORTA 0x005 byte PORTB 0x006 byte PORTC 0x007 byte PORTD 0x008 byte PORTE 0x009 byte PCLATH 0x00A byte INTCON 0x00B byte PIR1 0x00C byte PIR2 0x00D byte TMR1L 0x00E byte TMR1H 0x00F byte T1CON 0x010 byte TMR2 0x011 byte T2CON 0x012 byte SSPBUF 0x013 byte SSPCON 0x014 AN731 DS00731A page 66 Preliminary 2000 Microchip Technology Inc byte CCPR1L 0x015 byte CCPR1H 0x016 byte CCP1CON 0x017 byte RCSTA 0x018 byte TXREG 0x019 byte RCREG 0x01A byte CCPR2L 0x01B byte CCPR2H 0x01C byte CCP2CON 0x01D byte ADRESH 0x01E byte ADCON0 0x01F byte OPTION_REG 0x081 byte TRISA 0x085 byte TRISB 0x086 byte TRISC 0x087 byte TRISD 0x088 byte TRISE 0x089 byte PIE1 0x08C byte PIE2 0x08D byte PCON 0x08E byte SSPCON2 0x091 byte PR2 0x092 byte SSPADD 0x093 byte SSPSTAT 0x094 byte TXSTA 0x098 byte SPBRG 0x099 byte ADRESL 0x09E byte ADCON1 0x09F byte EEDATA 0x10C byte EEADR 0x10D byte EEDATH 0x10E byte EEADRH 0x10F byte EECON1 0x18C byte EECON2 0x18D STATUS Bits bit IRP STATUS 7 bit RP1 STATUS 6 bit RP0 STATUS 5 bit NOT_TO STATUS 4 bit NOT_PD STATU
37. 1 Start read operation DataPtr EEDATA Write read data into RAM EEADR Increment EEPROM address DataPtr Increment RAM address void Write_data void This routine writes the item names and prices to the internal EEPROM void Write_data void WriteIntEE 0x50 Item_1 9 WriteIntEE 0x60 Item_2 9 WriteIntEE 0x70 Price_1 5 WriteIntEE 0x78 Price_2 5 void Read_data void This routine reads the item names and prices from the internal EEPROM void Read_data void ReadIntEE 0x50 Item_1 9 ReadIntEE 0x60 Item_2 9 ReadIntEE 0x70 Price_1 5 ReadIntEE 0x78 Price_2 5 Filename GET_INFO C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 31 00 Compiled using CCS PICC This file contains the routine to prompt the user to enter new information such as username password and telephone number It also has a ro
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39. 1A page 35 AN731 lcd_send_byte 0 1 delay_ms 2 break case n new line lcd_gotoxy 1 2 break case b backspace lcd_send_byte 0 0x10 break default character lcd_send_byte 1 c break Filename F877 H Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 24 00 Compiled using CCS PICC This is a header file containing register and bit definitions for the PIC16F877 External Clock provided by Si2400 modem 9 8304MHz Registers byte INDF 0x000 byte TMR0 0x001 byte PCL 0x002 byte STATUS 0x003 byte FSR 0x004 byte PORTA 0x005 byte PORTB 0x006 byte PORTC 0x007 byte PORTD 0x008 byte PORTE 0x009 byte PCLATH 0x00A byte INTCON 0x00B byte PIR1 0x00C byte PIR2 0x00D byte TMR1L 0x00E byte TMR1H 0x00F byte T1CON 0x010 byte TMR2 0x011 byte T2CON 0x012 byte SSPBUF 0x013 byte SSPCON 0x014 byte CCPR1L 0x015 byte CCPR1H 0x016 byte CCP1CON 0x017 byte RCSTA 0x018 byte TXREG 0x019 byte RCREG 0x01A byte CCPR2L 0x01B byte CCPR2H 0x01C by
40. 2 3 bit PEN SSPCON2 2 bit RSEN SSPCON2 1 bit SEN SSPCON2 0 SSPSTAT Bits bit SMP SSPSTAT 7 bit CKE SSPSTAT 6 bit D_A SSPSTAT 5 bit P SSPSTAT 4 bit S SSPSTAT 3 bit R_W SSPSTAT 2 bit UA SSPSTAT 1 bit BF SSPSTAT 0 2000 Microchip Technology Inc Preliminary DS00731A page 39 AN731 TXSTA Bits bit CSRC TXSTA 7 bit TX9 TXSTA 6 bit TXEN TXSTA 5 bit SYNC TXSTA 4 bit BRGH TXSTA 2 bit TRMT TXSTA 1 bit TX9D TXSTA 0 ADCON1 Bits bit ADFM ADCON1 5 bit PCFG3 ADCON1 3 bit PCFG2 ADCON1 2 bit PCFG1 ADCON1 1 bit PCFG0 ADCON1 0 EECON1 Bits bit EEPGD EECON1 7 bit WRERR EECON1 3 bit WREN EECON1 2 bit EEWR EECON1 1 bit EERD EECON1 0 Filename S7600 H Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 24 00 Compiled using CCS PICC This file contains the register address definitions of the S 7600A External Clock prov
41. AN731 FIGURE D 3 TCP IP CLIENT SODA MACHINE SHEET 3 OF 3 3 V JP4 3 V C8 1 F C7 220 F C6 1 F 1 3 2 J3 DJ005B D3 5 V 3 OUT 1 IN 2 COM U6 LM2937 5 V 3 OUT 1 IN 2 COM U3 LM2937 3 3 V C9 1 F 3 V RXD2 TXD2 2 P2 4 P4 6 P6 8 P8 10 P10 12 P12 14 P14 16 P16 15 P15 13 P13 11 P11 9 P9 7 P7 5 P5 3 P3 1 P1 JP1 OSC1 RESET RXD CTS TXD DCD 6 R S 19 VSS 5 E 18 VCC 16 VEE 15 R W 14 DB4 13 DB5 12 DB6 11 DB7 17 LED LCD_SIMM LCD1 5 V B2 B3 B4 B5 B6 B7 B1 AN731 DS00731A page 44 Preliminary 2000 Microchip Technology Inc FIGURE D 4 WEB CLIENT FLOWCHART SHEET 1 OF 3 A B START INITIALIZE PIC16F877 AND LCD DISPLAY MENU BUTTON PRESSED YES NO RESET MODEM AND S 7600A CONFIGURE MODEM AND S 7600A RESET AND ENABLE PPP READ USER NAME PASSWORD AND WRITE TO PAP REGISTER READ PHONE NUMBER AND SEND TO MODEM TO DIAL DETECT BUSY OR NO LINE OR CARRIER YES NO CONNECT YES NO ENABLE PAP RELEASE CONTROL OF UART TO S 7600A NO IP ADDRESS CHANGE READ AND DISPLAY IP ADDRESS INITIALIZE DISPLAY WITH ITEM NAMES YES NO YES NO NO YES DISPENSE ITEM UPDATE DISPLAY DISPENSE ITEM UPDATE DISPLAY CONNECT BUTTON PRESSED
42. CD pins boolean rd_w The bits are allocated from boolean reg_sel low order up UNUSED will int data 4 be pin B0 lcd byte lcd 6 This puts the entire structure on to port B at address 6 STRUCT lcd_pin_map const LCD_WRITE 1 0 0 0 0 For write mode all pins are out except RB0 int1 include lcd_cut c LCD routines include seiko_ct c Seiko routines include Int_EE c Internal EEPROM include get_info c Get Username Password and Phone Number routines void Write_LCD_1 void Initializes text on LCD display void Write_LCD_1 void lcd_putc f LCD line 1 i 0 while Item_1 i Write text of Item 1 to LCD lcd_putc Item_1 i i lcd_gotoxy 9 1 LCD Line 1 pos 9 i 0 while Item_2 i Write text of Item 2 to LCD lcd_putc Item_2 i i lcd_gotoxy 3 2 LCD Line 2 pos 3 i strlen Price_2 i 0 while Price_1 i Write price of Item 1 to LCD lcd_putc Price_1 i i lcd_gotoxy 11 2 LCD Line 2 pos 11 i 0 while Price_2 i Write price of Item 2 to LCD lcd_putc Price_2 i i AN731 DS00731A page 50 Preliminary 2000 Microchip Technology Inc void dis
43. DCON0 Bits bit ADCS1 ADCON0 7 bit ADCS0 ADCON0 6 bit CHS2 ADCON0 5 bit CHS1 ADCON0 4 bit CHS0 ADCON0 3 AN731 DS00731A page 38 Preliminary 2000 Microchip Technology Inc bit GO ADCON0 2 bit NOT_DONE ADCON0 2 bit CHS3 ADCON0 1 bit ADON ADCON0 0 OPTION Bits bit NOT_RBPU OPTION_REG 7 bit INTEDG OPTION_REG 6 bit T0CS OPTION_REG 5 bit T0SE OPTION_REG 4 bit PSA OPTION_REG 3 bit PS2 OPTION_REG 2 bit PS1 OPTION_REG 1 bit PS0 OPTION_REG 0 TRISE Bits bit IBF TRISE 7 bit OBF TRISE 6 bit IBOV TRISE 5 bit PSPMODE TRISE 4 PIE1 Bits bit PSPIE PIE1 7 bit ADIE PIE1 6 bit RCIE PIE1 5 bit TXIE PIE1 4 bit SSPIE PIE1 3 bit CCP1IE PIE1 2 bit TMR2IE PIE1 1 bit TMR1IE PIE1 0 PIE2 Bits bit EEIE PIE2 4 bit BCLIE PIE2 3 bit CCP2IE PIE2 0 PCON Bits bit NOT_POR PCON 1 bit NOT_BOR PCON 0 SSPCON2 Bits bit GCEN SSPCON2 7 bit ACKSTAT SSPCON2 6 bit ACKDT SSPCON2 5 bit ACKEN SSPCON2 4 bit RCEN SSPCON
44. DCON1 1 bit PCFG0 ADCON1 0 EECON1 Bits bit EEPGD EECON1 7 bit WRERR EECON1 3 bit WREN EECON1 2 bit EEWR EECON1 1 bit EERD EECON1 0 Filename S7600 H Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 31 00 Compiled using CCS PICC This file contains the register address definitions of the S 7600A External Clock provided by Si2400 modem 9 8304MHz Seiko S 7600A TCP IP Stack IC Header File case define Revision 0x00 define General_Control 0x01 define General_Socket_Location 0x02 define Master_Interrupt 0x04 define Serial_Port_Config 0x08 AN731 DS00731A page 70 Preliminary 2000 Microchip Technology Inc define Serial_Port_Int 0x09 define Serial_Port_Int_Mask 0x0a define Serial_Port_Data 0x0b define BAUD_Rate_Div_L 0x0c define BAUD_Rate_Div_H 0x0d define Our_IP_Address_L 0x10 define Our_IP_Address_M 0x11 define Our_IP_Address_H 0x12 define Our_IP_Address_U 0x13 define Clock_Div_L 0x1c define Clock_Div_H 0
45. G CODE The programming sequence contains a five instruction sequence that must be executed exactly to initiate the programming cycle If this sequence is not followed the programming operation will not start Also included is a write enable bit If this bit is not set then writes will not take place These two features provide a measure of protection against inadvertent writes Features PIC16F870 PIC16F871 PIC16F872 PIC16F873 PIC16F874 PIC16F876 PIC16F877 Operating Frequency DC 20 MHz Resets Power on Reset Brown out Reset Power up Timer Oscillator Start up Timer FLASH Program Memory 2K 2K 2K 4K 4K 8K 8K Data Memory 128 128 128 192 192 368 368 EEPROM Data Memory 64 64 64 128 128 256 256 Interrupts 10 10 11 13 14 13 14 I O Pins 22 33 22 22 33 22 33 Timers 3 3 3 3 3 3 3 Capture Com pare PWM 1 1 1 2 2 2 2 Serial Communication USART USART MSSP MSSP USART MSSP USART MSSP USART MSSP USART Parallel Communication PSP PSP PSP 10 bit A D Channels 5 8 5 5 8 5 8 Instruction Set 35 Instructions Packages 28 pin DIP SOIC SSOP 40 pin DIP 44 pin PLCC TQFP 28 pin DIP SOIC SSOP 28 pin DIP SOIC 40 pin DIP 44 pin PLCC TQFP 28 pin DIP SOIC 40 pin DIP 44 pin PLCC TQFP bsf STATUS RP1 Switch to Bank 3 bsf STATUS RP0 bsf EECON1 WREN Enable write movlw 55h 5 instruction mowf EECON2 seque
46. K 11 CLR U8 SN74HC4040DW OSC1 CLK1 CLK 1 2 3 J1 SIP_3 CLK RESET RXD 1 F C1 DCD BUSYX WRITEX READX RS CS 3 V 3 V INT1 C5 1 F 1 F C12 3 V for U8 SD0 SD1 SD2 SD3 SD4 SD5 VDD TI1 TI2 NC SD7 SD6 SD0 SD1 SD2 SD3 SD4 SD5 SD6 SD7 48 47 46 45 44 43 42 41 40 39 38 37 T07 T06 T05 T04 T03 T02 T01 VDD T17 T16 T15 T14 13 14 15 16 17 18 19 20 21 22 23 24 2000 Microchip Technology Inc Preliminary DS00731A page 13 AN731 FIGURE B 3 TCP IP SERVER MODEM SHEET 3 OF 3 3 V JP4 3 V C8 1 F C7 220 F C6 1 F 1 3 2 J3 DJ005B D3 3 V 5 V 3 OUT 1 IN 2 COM U6 LM2937 5 V 3 OUT 1 IN 2 COM U3 LM2937 3 3 V C9 1 F RB7 RB6 RB5 RB4 RB3 RB1 RB2 3 V RXD2 TXD2 2 P2 4 P4 6 P6 8 P8 10 P10 12 P12 14 P14 16 P16 15 P15 13 P13 11 P11 9 P9 7 P7 5 P5 3 P3 1 P1 JP1 OSC1 RESET RXD CTS TXD DCD B1 B2 B3 B4 B5 B6 B7 6 R S 19 VSS 5 E 18 VCC 16 VEE 15 R W 14 DB4 13 DB5 12 DB6 11 DB7 17 LED LCD_SIMM LCD1 5 V B2 B3 B4 B5 B6 B7 B1 R2 10 k 3 Y4 5 Y3
47. S 3 bit Z STATUS 2 bit DC STATUS 1 bit C STATUS 0 INTCON Bits bit GIE INTCON 7 bit PEIE INTCON 6 bit T0IE INTCON 5 bit INTE INTCON 4 bit RBIE INTCON 3 bit T0IF INTCON 2 bit INTF INTCON 1 bit RBIF INTCON 0 PIR1 Bits bit PSPIF PIR1 7 bit ADIF PIR1 6 bit RCIF PIR1 5 2000 Microchip Technology Inc Preliminary DS00731A page 67 AN731 bit TXIF PIR1 4 bit SSPIF PIR1 3 bit CCP1IF PIR1 2 bit TMR2IF PIR1 1 bit TMR1IF PIR1 0 PIR2 Bits bit EEIF PIR2 4 bit BCLIF PIR2 3 bit CCP2IF PIR2 0 T1CON Bits bit T1CKPS1 T1CON 5 bit T1CKPS0 T1CON 4 bit T1OSCEN T1CON 3 bit NOT_T1SYNC T1CON 2 bit T1INSYNC T1CON 2 bit TMR1CS T1CON 1 bit TMR1ON T1CON 0 T2CON Bits bit TOUTPS3 T2CON 6 bit TOUTPS2 T2CON 5 bit TOUTPS1 T2CON 4 bit TOUTPS0 T2CON 3 bit TMR2ON T2CON 2 bit T2CKPS1 T2CON 1 bit T2CKPS0 T2CON 0 SSPCON Bits bit WCOL SSPCON 7 bit SSPOV SSPCON 6 bit SSPEN SSPCON 5 bit CKP SSPCON 4 bit SSPM3 SSPCON 3 bit SSPM2 SSPCON 2 bit SSPM1 SSPCON 1
48. This information is dynamically inserted into the web page as it is transmitted The other mode is a configuration mode that allows the ISP information and web page to be downloaded into the serial EEPROM The ISP information includes the phone number user name and password The size of the serial EEPROM is application dependent It can range from 16 bytes 24LC00 to 32 Kbytes 24LC256 The board is currently using a 16 Kbyte device the 24LC64 To configure the web server the RS 232 inter face on the modem evaluation board is connected to the USART module on the PIC16F877 Ring Detect DC Termination Ring Impedance AC Termination Ring Threshold AFE Hybrid Isolation Interface Isolation Interface To Host Digital Interface Micro Controller DSP Si2400 Si3015 To Telephone Line Data Control ISOcap AN731 DS00731A page 8 Preliminary 2000 Microchip Technology Inc Any terminal program will work as the PIC16F877 dis plays a text menu that allows the user several options 1 Enter user name 2 Enter password 3 Enter phone number 4 Download HTML file 5 Or exit configuration mode Each piece of information has specific memory loca tions reserved in the serial EEPROM 32 bytes are reserved for both the user name and password The ISP phone number takes an additional 16 bytes Finally 32688 bytes are available to store the HTML file The serial interface must use hardware
49. _Port_H 0x39 define Socket_Status_H 0x3a define Their_IP_Address_L 0x3c define Their_IP_Address_M 0x3d define Their_IP_Address_H 0x3e define Their_IP_Address_U 0x3f define PPP_Control_Status 0x60 define PPP_Interrupt_Code 0x61 define PPP_Max_Retry 0x62 define PAP_String 0x64 2000 Microchip Technology Inc Preliminary DS00731A page 41 AN731 APPENDIX D WEB CLIENT SCHEMATICS FIGURE D 1 TCP IP CLIENT SODA MACHINE SHEET 1 OF 3 34 VSS 35 VDD 2 MCLR 3 RA0 4 RA1 5 RA2 6 RA3 7 RA4 8 RA5 36 RB0 37 RB1 38 RB2 39 RB3 41 RB4 42 RB5 43 RB6 44 RB7 13 VSS 14 OSC1 15 OSC2 16 RC0 18 RC1 19 RC2 20 RC3 25 RC4 26 RC5 27 RC6 29 RC7 21 RD0 22 RD1 23 RD2 24 RD3 30 RD4 31 RD5 32 RD6 33 RD7 11 RE2 10 RE1 9 RE0 12 VDD U1 PIC16F877 RB6 RB7 RB5 CTS OSC1 CLK1 RC3 RC4 RB4 RB3 RB2 R8 300 R5 300 SD6 RA3 RS CS WRITEX READX SD5 SD4 SD3 SD2 RB1 RESET BUSYX SD0 SD7 SD1 RXD2 TXD2 MCLR R1 10 k 1 F C4 3 V C2 1 F 3 V C3 1 F 3 V D1 D2 RA1 INT1 RB6 RB7 MCLR 1 2 3 4 6 5 JP2 RJ11_6PIN 3 V 4 3 2 1 S1 MCLR 4 3 2 1 S2 4 3 2 1 S3 4 3 2 1 S4 RC3 RA0 RA1
50. a web server and a client The web server stores the HTML page in an external serial EEPROM and dynamically inserts temperature and potentiometer settings into the HTML file as it is being sent The client application mimics a vending machine that uploads status informa tion at predefined intervals This application note was written with the assumption that the reader has a basic level of knowledge of Inter net protocols There are many good books on the mar ket that describe the Internet and all the various protocols used It is suggested that the reader obtain one of these books to understand what the protocols are used for and how they relate to other protocols Appendix A is a dictionary of the terms used in this application note FIGURE 1 BLOCK DIAGRAM Author Rodger Richey Steve Humberd Microchip Technology Inc Chandler AZ PIC16F877 MSSP CCP A D USART Physical Layer Interface 16 byte FIFO 1 byte Buffer UART DSP Micro controller Si2400 Si3015 ISOcap Interface Ring Detect DC AC Termination AFE Codec External Discretes TIP RING S 7600A SRAM 10 Kbytes SRAM Interface MPU Interface Network Stack UDP TCP IP PPP Embedding PICmicro Microcontrollers in the Internet AN731 DS00731A page 2 Preliminary 2000 Microchip Technology Inc EMBEDDED WEB SERVER VS CLIENT When most people think of the Internet they think about viewing web pages fi
51. adSeiko Socket_Status_H delay_ms 5000 wait five more seconds to be sure socket is closed EEPROM addresses username00 1F32 bytes password20 3F32 bytes Phone 40 4F16 bytes Filename SEIKO_CT C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 24 00 Compiled using CCS PICC This file contains the routines to read and write data to the S 7600A External Clock provided by Si2400 modem 9 8304MHz void WriteSeiko char address char data Writes a byte of data to a register on the S 7600A void WriteSeiko char address char data while BUSY Wait for S 7600A CS 1 1st cycle sets register address RS 0 WRITEX 0 PORTD address Send address TRISD 0 READX 1 READX 0 WRITEX 1 RS 1 CS 0 CS 1 2nd cycle sends data WRITEX 0 PORTD data Send data READX 1 READX 0 WRITEX 1 CS 0 TRISD 0xff AN731 DS00731A page 32 Preliminary
52. ainal printf c 12 20H 32 chars max esc printf c 10 20H Enter user name esc while 1 Read characaters until a CR is read or 32 chars user i 0 have been read ch GETC if ch 0x0D break putc ch if ch 0x08 user i ch i if i 32 break write user name to the EEPROM n_tmp 0 for i 0 i lt 0x1F i ch user i write_ext_eeprom n_tmp user i n_tmp void Get_password void Requests and reads the password from the input terminal void Get_password byte a_tmp i 0 printf c 2J esc Print request to terminal printf c 12 20H 32 chars max esc printf c 10 20H Enter password esc while 1 Read characters until a 2000 Microchip Technology Inc Preliminary DS00731A page 21 AN731 CR is read or 16 chars pass i 0 have been read ch getc if ch 0x0D break if ch 0x0A line feed putc ch if ch 0x08 pass i ch i if i 16 break write password to the EEPROM a_tmp 0x20 for i 0 i lt 0x1F i ch pass i write_ext_eeprom a_tmp pass i a_tmp void Get_phone void Requests and reads the telephone number from the input terminal
53. ak done if ch b busy tone detected lcd_putc busy reset amp start over printf nbusy r gotorestart if ch l No phone line detected gotorestart if ch N No carrier detected gotorestart ch 0 lcd_putc fConnect printf nConnect r LED1 0 LED1 ON WriteSeiko PPP_Control_Status 0x62 Use PAP enable PPP WriteSeiko Serial_Port_Config 0x01 turn serial port over to S 7600 delay_ms 5 Register 0x60 wait for PPP to be Up while ReadSeiko PPP_Control_Status amp 0x01 delay_ms 5 AN731 DS00731A page 28 Preliminary 2000 Microchip Technology Inc while ReadSeiko Our_IP_Address_L 0 detect when ready to proceed MyIPAddr 0 ReadSeiko Our_IP_Address_L Read the assigned IP address MyIPAddr 1 ReadSeiko Our_IP_Address_M of the web server MyIPAddr 2 ReadSeiko Our_IP_Address_H MyIPAddr 3 ReadSeiko Our_IP_Address_U Print address to the terminal and LCD printf r nMy address is u u u u MyIPAddr 3 MyIPAddr 2 MyIPAddr 1 MyIPAddr 0 lcd_putc fMy address is n printf lcd_putc u u u u MyIPAddr 3 MyIPAddr 2 MyIPAddr 1 MyIPAddr 0 Main Webserver Loop while 1 while 1 delay_ms 1 Check to see if PPP is still up or modem has disconnected if ReadSeiko PPP_Control_Status amp 0x01 gotorestart if ReadSeiko Serial_Port_Config amp 0x40 gotoresta
54. ccuracy or use of such information or infringement of patents or other intellectual property rights arising from such use or otherwise Use of Microchip s products as critical components in life support systems is not authorized except with express written approval by Microchip No licenses are conveyed implicitly or otherwise except as maybe explicitly expressed herein under any intellectual property rights The Microchip logo and name are registered trademarks of Microchip Technology Inc in the U S A and other countries All rights reserved All other trademarks mentioned herein are the property of their respective companies DS00731A page 72 Preliminary 2000 Microchip Technology Inc All rights reserved 6 23 00 Microchip Technology Incorporated Printed in the USA Friday June 23 2000 Printed on recycled paper AMERICAS Corporate Office Microchip Technology Inc 2355 West Chandler Blvd Chandler AZ 85224 6199 Tel 480 786 7200 Fax 480 786 7277 Technical Support 480 786 7627 Web Address http www microchip com Atlanta Microchip Technology Inc 500 Sugar Mill Road Suite 200B Atlanta GA 30350 Tel 770 640 0034 Fax 770 640 0307 Boston Microchip Technology Inc 2 LAN Drive Suite 120 Westford MA 01886 Tel 508 480 9990 Fax 508 480 8575 Chicago Microchip Technology Inc 333 Pierce Road Suite 180 Itasca IL 60143 Tel 630 285 0071 Fax 630 285 0075 Dallas Microchip Technology Inc 4570 Westgrove Drive Suite
55. changes very slowly and the fact that another reading will be sent in a couple of min utes would allow extraction of the missing reading from the previously received reading and the current read ing UDP can come close to achieving some of the fea tures of TCP but it involves a lot of work to provide the handshaking necessary to create a reliable connection Many microcontroller manufacturers have software libraries that support TCP and UDP However most of these implementations have documented limitations that may cause increased overhead to transmit and receive data using Internet protocols The following bul lets list some of these limitations documented by a manufacturer for their UDP and TCP software imple mentations The UDP amp TCP headers contain a checksum field This checksum is computed for the data in the packet yet it is transmitted in the header This implementation transmits the packet with an incorrect checksum calculates the checksum as the packet is sent and sends the packet again with the correct checksum The implementation does not handle fragmented packets meaning that packets that arrive out of sequence are handled as sequential packets This causes the resulting data to be corrupted The proposed method assumes that if the packet size is minimized to 256 bytes then fragmentation is not likely to occur The implementation does not send a terminate acknowledge packet which forces the host on the
56. clude lt string h gt fuses HS NOWDT NOPROTECT NOBROWNOUT define EEPROM_SDA PIN_C4 define EEPROM_SCL PIN_C3 define hi x amp x 1 use delay clock 9828606 use rs232 baud 2400 xmit PIN_C6 rcv PIN_C7 use standard_io C use i2c master sda EEPROM_SDA scl EEPROM_SCL define EEPROM_ADDRESS long int define EEPROM_SIZE 1024 define esc 0x1b ESC char AN731 DS00731A page 18 Preliminary 2000 Microchip Technology Inc PORTA bits bit RS PORTA 2 bit RESET PORTA 4 bit BUSY PORTA 5 PORTB bits bit INT1 PORTB 0 As defined in the following structure the pin connection is as follows B1 enable B3 reg_sel B2 rd_w B4 D4 B5 D5 B6 D6 B7 D7 define lcd_type 2 0 5x7 1 5x10 2 2 lines define lcd_line_two 0x40 LCD RAM address for the second line byte lcd_cmd cmd_tmp byte CONST LCD_INIT_STRING 4 0x20 lcd_type lt lt 2 0xc 1 6 These bytes need to be sent to the LCD to start it up PORTC bits bit CTS PORTC 0 When CTS 0 send is enabled bit LED1 PORTC 2 When LED 0 the LED is ON bit LED2 PORTC 5 When LED 0 the LED is ON PORTE bits bit READX PORTE 0 bit WRITEX PORTE 1 bit CS PORTE 2 char i j ch addr temp pot ftmp ctmp count count1 page long index byt_cnt hits char Login 10 char MyIPAddr 4 char user 33 char pass 33 char phone 17 char read_data 5 char test_str 7 char read_Q 7
57. cluded are a potentiometer and a DS1721 temperature IC This design can be found using the link http 198 175 253 101 It takes up to 30 seconds or more for the web page to load Remember that we are transmitting several thousand bytes of information over the Internet at 2400 baud The schematic for everything but the modem and serial port interface is shown on the schematic in Appendix B This design was actually built around a modem evalua tion board from Silicon Laboratories Since the modem must meet FCC or other governing body regulations the schematics are not provided for the modem evalu ation board The schematics and layout considerations for the Si2400 Si3015 can be obtained from the Silicon Laboratories website The source code and flowchart for the web server are in Appendix C The source code was written using the C Compiler from Custom Computer Services Inc CCS More information about the compiler can be found on their website at http www ccsinfo com The web server has two modes of operation One is the standard web server mode where the device makes a phone call to the local ISP and establishes an IP address The user may access the web page by typing in the IP address displayed on the LCD display into any web browser It takes 30 to 40 seconds for the web page to load The web page shows some variable infor mation such as number of hits temperature where the web server is IP address and a potentiometer setting
58. dress select register to write delay_cycles 1 lcd rd_w 0 set for writes delay_cycles 1 lcd enable 0 lcd_send_nibble n gt gt 4 write data byte in nibbles lcd_send_nibble n amp 0xf TRISB 0xfd void lcd_init void Initializes the LCD display void lcd_init byte i set_tris_b LCD_WRITE set tris bits lcd reg_sel 0 select configuration lcd enable 0 delay_ms 15 lcd_send_byte 0 0x28 Write config info lcd_send_byte 0 0x0C lcd_send_byte 0 0x01 TRISB 0xfd void lcd_gotoxy byte x byte y Changes the cursor position to x y void lcd_gotoxy byte x byte y byte address if y 1 Check for line 1 or 2 address lcd_line_two else address 0 address x 1 lcd_send_byte 0 0x80 address Write cursor position void lcd_putc char c Writes the byte c to the current cursor position Routine detects form feeds returns and backspaces void lcd_putc char c switch c case f form feed 2000 Microchip Technology Inc Preliminary DS0073
59. echnology Inc Preliminary DS00731A page 37 AN731 T1CON Bits bit T1CKPS1 T1CON 5 bit T1CKPS0 T1CON 4 bit T1OSCEN T1CON 3 bit NOT_T1SYNC T1CON 2 bit T1INSYNC T1CON 2 bit TMR1CS T1CON 1 bit TMR1ON T1CON 0 T2CON Bits bit TOUTPS3 T2CON 6 bit TOUTPS2 T2CON 5 bit TOUTPS1 T2CON 4 bit TOUTPS0 T2CON 3 bit TMR2ON T2CON 2 bit T2CKPS1 T2CON 1 bit T2CKPS0 T2CON 0 SSPCON Bits bit WCOL SSPCON 7 bit SSPOV SSPCON 6 bit SSPEN SSPCON 5 bit CKP SSPCON 4 bit SSPM3 SSPCON 3 bit SSPM2 SSPCON 2 bit SSPM1 SSPCON 1 bit SSPM0 SSPCON 0 CCP1CON Bits bit CCP1X CCP1CON 5 bit CCP1Y CCP1CON 4 bit CCP1M3 CCP1CON 3 bit CCP1M2 CCP1CON 2 bit CCP1M1 CCP1CON 1 bit CCP1M0 CCP1CON 0 RCSTA Bits bit SPEN RCSTA 7 bit RX9 RCSTA 6 bit SREN RCSTA 5 bit CREN RCSTA 4 bit ADDEN RCSTA 3 bit FERR RCSTA 2 bit OERR RCSTA 1 bit RX9D RCSTA 0 CCP2CON Bits bit CCP2X CCP2CON 5 bit CCP2Y CCP2CON 4 bit CCP2M3 CCP2CON 3 bit CCP2M2 CCP2CON 2 bit CCP2M1 CCP2CON 1 bit CCP2M0 CCP2CON 0 A
60. eiko Socket_Data Read characters until a putc temp is read to indicate start if temp of data temp ReadSeiko Socket_Data putc temp i 0 while temp Read until a is reached to delimit Item1 from Item2 temp ReadSeiko Socket_Data putc temp Item_1 i temp i Item_1 i 0 i 0 while temp Read until a is reached to delimit Item2 from Price1 temp ReadSeiko Socket_Data putc temp Item_2 i temp i Item_2 i 0 i 0 while temp Read until a is reached to delimit Price1 from Price2 temp ReadSeiko Socket_Data putc temp Price_1 i temp i Price_1 i 0 i 0 while temp Read until a is reached to read all of Price2 temp ReadSeiko Socket_Data AN731 DS00731A page 56 Preliminary 2000 Microchip Technology Inc putc temp Price_2 i temp i Price_2 i 0 Ensure that socket is inactive count 0 bit_clear PIR1 TMR1IF clear interrupt flag while 0x40 ReadSeiko 0x22 amp 0x40 if bit_test PIR1 TMR1IF count bit_clear PIR1 TMR1IF clear interrupt flag Close Socket printf close socket n LED2 1 turn LED2 OFF WriteSeiko Socket_Activate 0 close the socket WriteSeiko TCP_Data_Send 0 Wait for Socket To Close 2 5 seconds Max can shorten in most cases if we ve waited
61. es of data EEPROM memory By combining both a data EEPROM and FLASH program memory the designer has the flexibility to store data in the appropriate place Information that is updated frequently can be stored in the data EEPROM which has increased endurance over the FLASH program memory This data can be modified without interrupting the operation of the appli cation Other information that is rarely changed can be stored in FLASH program memory When updating these locations the microcontroller ceases to execute instructions but continues to clock the peripherals and queue interrupts The programming operation is self timed i e an inter nal clock source applies the high voltage to the memory cells to erase and or write the data for a predetermined amount of time This frees the designer from the task of timing the event It also reduces the risk of the high volt age being applied too long which damages or reduces the endurance of the cell or not long enough which does not fully program the memory location The actual programming code is shown in Example 1 This simple piece of code assumes the addresses of the memory location and data have been loaded before being called The only difference between modifying FLASH program memory and data EEPROM memory is the setting of a single bit This bit needs to be configured only once and all subsequent programming operations will be directed to the desired memory EXAMPLE 1 SELF TIMIN
62. ets across a net work IP Address A 32 bit unique numeric address used by a computer on a TCP IP network LCP Link Control Protocol The protocol that negotiates the parameters used by the link between two computers and is protocol within PPP NCP Network Control Protocol The proto col within PPP that negotiates the type of network connection made by the two computers POP3 Post Office Protocol version 3 The protocol that you use to download e mail from a POP3 mail server to your computer port A number used by TCP and UDP to indicate which application is sending or receiving data PPP Point to Point Protocol A protocol that provides a serial line connectiv ity that is a dial up with a modem between two computers between a computer and a network or between two networks PPP can handle sev eral protocols simultaneously protocol Rules and message formats for communication between computers in a network protocol layers The divisions of a hierarchical net work model Each layer performs a service on behalf of the layer directly above it Each layer receives ser vices from the layer directly below it protocol stack A group of protocols that work together across network layers server A computer program that provides services to clients and or the com puter that runs the server program SMTP Simple Mail Transfer Protocol The TCP IP protocol for sending and receiving e mail across a networ
63. for the buffer to empty above for i 0 i lt 255 i delay_ms 10 temp ReadSeiko Socket_Status_M if temp amp 0x0f 0x08 Socket closed break if temp amp 0xe0 Error detected break printf n rfinal socket wait n LED2 1 LED OFF while ReadSeiko Socket_Status_H delay_ms 5000 wait five more seconds to be sure socket is closed Hang Up Modem by reseting everything RESET 0 LED1 1 LED OFF delay_ms 1 RESET 1 lcd_putc fUpdate Complete n At this point the program freezes until the user removes power The new downloaded values are saved in EEPROM and when power is applied these new values will be used for item names and prices lcd_putc Power Down while 1 2000 Microchip Technology Inc Preliminary DS00731A page 57 AN731 Filename SEIKO_CT C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 31 00 Compiled using CCS PICC This file contains the routines to read and write data to the S 7600A void WriteSeiko cha
64. ided by Si2400 modem 9 8304 MHz Seiko S 7600A TCP IP Stack IC Header File case define Revision 0x00 define General_Control 0x01 define General_Socket_Location 0x02 define Master_Interrupt 0x04 define Serial_Port_Config 0x08 define Serial_Port_Int 0x09 define Serial_Port_Int_Mask 0x0a define Serial_Port_Data 0x0b define BAUD_Rate_Div_L 0x0c define BAUD_Rate_Div_H 0x0d define Our_IP_Address_L 0x10 define Our_IP_Address_M 0x11 define Our_IP_Address_H 0x12 define Our_IP_Address_U 0x13 define Clock_Div_L 0x1c define Clock_Div_H 0x1d define Socket_Index 0x20 define Socket_TOS 0x21 AN731 DS00731A page 40 Preliminary 2000 Microchip Technology Inc define Socket_Config_Status_L 0x22 define Socket_Status_M 0x23 define Socket_Activate 0x24 define Socket_Interrupt 0x26 define Socket_Data_Avail 0x28 define Socket_Interrupt_Mask_L 0x2a define Socket_Interrupt_Mask_H 0x2b define Socket_Interrupt_L 0x2c define Socket_Interrupt_H 0x2d define Socket_Data 0x2e define TCP_Data_Send 0x30 define Buffer_Out_L 0x30 define Buffer_Out_H 0x31 define Buffer_In_L 0x32 define Buffer_In_H 0x33 define Urgent_Data_Pointer_L 0x34 define Urgent_Data_Pointer_H 0x35 define Their_Port_L 0x36 define Their_Port_H 0x37 define Our_Port_L 0x38 define Our
65. ine feed putc ch if ch 0x08 pass i ch i if i 16 break write password to the Internal EEPROM WriteIntEE 0x20 pass 0x1f AN731 DS00731A page 64 Preliminary 2000 Microchip Technology Inc void Get_phone void Requests and reads the telephone number from the input terminal void Get_phone Print request to terminal printf c 2J esc printf c 12 20H 16 chars max esc printf c 10 20H Enter phone number esc i 0 while 1 Read characters until a CR is read or 16 chars phone i 0 have been read ch getc if ch 0x0D break if ch 0x0A line feed putc ch if ch 0x08 phone i ch i if i 16 break write phone number to the Internal EEPROM WriteIntEE 0x40 phone 16 void Write_data_to_rs232 void Debugging routine that dumps the contents of the EEPROM to the terminal Must uncomment line in main void Write_data_to_rs232 void Read and print data EEPROM contents for index 0 index lt 0x50 index ReadIntEE index amp ch 1 temp isalnum ch if temp putc ch else putc
66. is reached index 0x50 ch 1 while ch ch read_ext_eeprom index putc ch temp ch index temp index gt gt 8 ch 1 void Menu void Displays menu on user s terminal screen Allows changes to username password phone number and web page void Menu void i 0 CTS 0 enable send Print main menu to terminal escape terminates while ch 0x1b lcd_putc fPC Terminal menu printf c 2J esc printf c 8 25H 1 Enter user name esc printf c 10 25H 2 Enter password esc printf c 12 25H 3 Enter phone number esc printf c 14 25H 4 Down load HTML file esc printf c 17 30H ESC exit esc ch getc Get input and process switch ch case 0x31 1 gt change username Get_username break case 0x32 2 gt change password Get_password break case 0x33 3 gt change phone AN731 DS00731A page 24 Preliminary 2000 Microchip Technology Inc Get_phone break case 0x34 4 gt new web page Read_file break CTS 1 disable send void temp_config byte data Configures DS1721 temperature measurement IC using the I2C module
67. ister RS 0 address WRITEX 0 PORTD Socket_Data Write to socket TRISD 0 READX 1 READX 0 WRITEX 1 RS 1 CS 0 CS 1 2nd writes the data to WRITEX 0 the register PORTD data Data to write READX 1 READX 0 WRITEX 1 CS 0 TRISD 0xff Filename LCD_CUT C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 31 00 Compiled using CCS PICC This file contains the LCD interface routines to send a nibble byte initialize the LCD goto an x y coordinate and write a byte External Clock provided by Si2400 modem 9 8304MHz void lcd_send_nibble byte n Writes 4 bits of information to the LCD display void lcd_send_nibble byte n lcd data n Write nibble to port delay_cycles 1 delay lcd enable 1 clock data in delay_us 2 lcd enable 0 void lcd_send_byte byte address byte n
68. k socket A data structure that allows pro grams on an internet to communi cate It works as a pipeline between the communicating programs and consists of an address and a port number TCP Transmission Control Protocol One of the two principal components of a TCP IP protocol suite TCP puts data into packets and provides reli able packet delivery across a net work packets arrive in order and are not lost UDP User Datagram Protocol A TCP IP protocol found at the network inter net layer along with the TCP proto col UDP sends data down to the internet layer and to the IP protocol Unlike TCP UDP does not guaran tee reliable sequenced packet deliv ery If data does not reach its destination UDP does not retrans mit as TCP does Most definitions provided by the book TCP IP for Dum mies 3rd Edition by Candace Leiden and Marshall Wilensky and published by IDG Books Worldwide Inc ISBN 0 7645 0473 8 2000 Microchip Technology Inc Preliminary DS00731A page 11 AN731 APPENDIX B EMBEDDED WEB SERVER SCHEMATICS FIGURE B 1 TCP IP SERVER MODEM SHEET 1 OF 3 34 VSS 35 VDD 2 MCLR 3 RA0 4 RA1 5 RA2 6 RA3 7 RA4 8 RA5 36 RB0 37 RB1 38 RB2 39 RB3 41 RB4 42 RB5 43 RB6 44 RB7 13 VSS 14 OSC1 15 OSC2 16 RC0 18 RC1 19 RC2 20 RC3 25 RC4 26 RC5 27 RC6 29 RC7 21 RD0 22 RD1 23 RD2 24 RD3 30 RD4
69. kingham Berkshire England RG41 5TU Tel 44 118 921 5858 Fax 44 118 921 5835 05 16 00 WORLDWIDE SALES AND SERVICE Microchip received QS 9000 quality system certification for its worldwide headquarters design and wafer fabrication facilities in Chandler and Tempe Arizona in July 1999 The Company s quality system processes and procedures are QS 9000 compliant for its PICmicro 8 bit MCUs KEELOQ code hopping devices Serial EEPROMs and microperipheral products In addition Microchip s quality system for the design and manufacture of development systems is ISO 9001 certified
70. lated with a header and a checksum to provide some error checking Unlike UDP Transmission Control Protocol TCP pro vides a flow controlled connection based host to host transfer of data TCP provides connections based on IP address and ports Each of the source and destination devices have different IP addresses but both devices must be using the same port to be able to communicate to each other The number of the port used usually determines what type of application layer is used for communication These port numbers may be from 0 to 65536 but some are already assigned to specific appli cations A port number of 80 is usually assigned to HTTP Therefore an HTTP server will listen to port 80 for any incoming data The HTTP server will accept data packets if the destination IP address and the port number match A large data file will be broken up into many packets of data TCP is capable of receiving these packets in any order and then reconstructing the original file TCP also has the same type of checksums that are involved with UDP TCP has been deemed to be the more reliable method of transferring data over the Internet but it really depends on the type of data being transferred between the two devices One factor is the relative importance of the data If a device is transmitting temperature mea surements every couple of minutes losing one reading may not be as severe as losing one frame of data in an image file Temperature
71. laws All rights are reserved Any use in violation of the foregoing restrictions may subject the user to criminal sanctions under applicable laws as well as to civil liability for the breach of the terms and conditions of this license THIS SOFTWARE IS PROVIDED IN AN AS IS CONDITION NO WARRANTIES WHETHER EXPRESS IMPLIED OR STATU TORY INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICU LAR PURPOSE APPLY TO THIS SOFTWARE THE COMPANY SHALL NOT IN ANY CIRCUMSTANCES BE LIABLE FOR SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR ANY REASON WHATSOEVER APPENDIX E WEB CLIENT SOURCE CODE Filename SODA_TCP C Author Stephen Humberd Rodger Richey Company Microchip Technology Revision RevA0 Date 5 30 00 Compiled using CCS PICC Include files 16f877 h f877 h s7600 h ctype h string h lcd_cut c seiko_ct c int_ee c get_info c This program demonstrates a simple WEB client using a Microchip PIC16F877 microcontroller and a Seiko S 7600 TCP IP Network Protocol chip This is the main file that includes all other header files and source code fi
72. les External Clock provided by Si2400 modem 9 8304 MHz Internal EEPROM Addresses User Name 0x00 to 0x1F Password 0x20 to 0x3F Phone Number 0x40 to 0x4F Item_1 0x50 to 0x58 Item_2 0x60 to 0x68 Price_1 0x70 to 0x74 Price_2 0x78 to 0x7C Edit Line 52 to change Default Quantity Edit Line 53 54 to change Port Edit Line 55 58 to change Their IP Address include f877 h include lt 16f877 h gt include s7600 h include lt ctype h gt include lt string h gt fuses HS NOWDT NOPROTECT NOBROWNOUT AN731 DS00731A page 48 Preliminary 2000 Microchip Technology Inc use delay clock 9828606 use rs232 baud 2400 xmit PIN_C6 rcv PIN_C7 define esc 0x1b ESC char for VT 100 emulation PORTA bits bit RS PORTA 2 bit RESET PORTA 4 bit BUSY PORTA 5 PORTB bits bit INT1 PORTB 0 As defined in the following structure the pin connection is as follows B1 enable B3 reg_sel B2 rd_w B4 D4 B5 D5 B6 D6 B7 D7 define QUAN 5 Default quantity of Items in Vending Machine define PORT_H 0x1F IP Port define PORT_L 0x90 define T_Address_163 Their IP Address define T_Address_2 224 define T_Address_3 145 define T_Address_4 51 define lcd_type 2 0 5x7 1 5x10 2 2 lines
73. lled with information A com puter of some sort provides the necessary resources required to support a web server The computer has significant hard disk space to hold the web pages and ancillary data files such as data sheets application notes etc It also has a high speed communications interface such as a T1 line a 56K modem etc that can serve this information to a user quickly Embedded systems are quite different from standard web servers They have limited resources in terms of memory space and operating speed Embedded sys tems usually work with a few kilobytes up to several megabytes of memory and operate up to 40 MHz Typ ical PCs have several gigabytes of memory storage and are starting to operate in the gigahertz range Therefore web servers are not really practical for embedded applications but the embedded web client is very practical One of the most viable embedded web client applica tions is a vending machine The microcontroller keeps track of all functions Price for each item Number of items left Amount of deposited money Amount of money available for change One could also argue that the machine could keep track of the name or type of items that it is dispensing On a preset interval such as once a night between 11 PM and 4 AM the vending machine would dial out and make a connection to a local Internet Service Pro vider ISP The machine would then connect to a server and upload all
74. n temperature 2000 Microchip Technology Inc Preliminary DS00731A page 25 AN731 void main void void main void Intialize PORTs amp TRISs PORTA 0x24 00100100 PORTB 0xff 00000000 PORTD 0 00000000 PORTE 0xFA 11111010 TRISA 0xE3 11100011 TRISB 0xff TRISC 0x98 10011000 TRISD 0xff 11111111 TRISE 0 00000000 ADCON1 0x06 00000110all digital to start ADCON0 0 PR2 0x07 Enable PWM CCPR2L 0x03 CCP2CON 0x0C 00001100 T2CON 0x04 00000100 T1CON 0x31 00110001Timer1 LED1 1 LED OFF LED2 1 CTS 1 disable send hits 0 init_ext_eeprom initalize I2C init_temp initalize DS1721 temperature chip lcd_init initalize the LCD ch bit_test PORTA 1 test for menu button if ch 0 Menu Show enter menu ADCON1 0x04 00000100 ADCON0 0x81 10000001 Write_data_to_rs232 This routine dumps all data stored in the EEPROM to the PC terminal it is used for debug only Program starts here Modem is hard reset configured and waits for a request on the HTTP port 80 restart LED1 1 LED OFF LED2 1 RESET 0 Reset modem and S 7600A delay_ms 1 RESET 1 lcd_putc fReseting Modem n printf n rReseting
75. nce to movlw AAh initiate the movwf EECON2 write operation bsf EECON1 WR to memory nop nop AN731 DS00731A page 4 Preliminary 2000 Microchip Technology Inc The other part of the remote programming operation handled by the microcontroller is the bootloader This portion of the firmware accepts data from the outside world and controls the erase program operations It may also include security features for entering the pro gramming mode One feature that is a must in all boot loaders is the capability to recover when the communications medium is interrupted If the Internet connection or telephone connection is interrupted the microcontroller must be smart enough to recover The application note AN732 provides one method for recov ery The security portion is not implemented because requirements are heavily dependent on the application TCP IP STACK The Internet protocol used varies depending on the application Figure 2 shows the standard Internet pro tocol stack In most embedded systems a dial up con nection will be used and therefore the Network Access Layer will be Point to Point Protocol PPP This protocol encapsulates the other protocols for transmission over serial links such as modems This is the most commonly used protocol for dial up networks such as America Online Inc or Compuserve PPP performs three main functions It encapsulates IP and TCP UDP packets with a header and checksum and
76. ng DataPtr address in RAM to read data for writing NumBytes number of bytes to write void WriteIntEE char Addr char DataPtr char NumBytes char i EEADR Addr Set starting address EEPGD 0 Select data EEPROM WREN 1 Enable Writes for i 0 i lt NumBytes i EEIF 0 Clear interrupt flag EEDATA DataPtr Set data to write WREN 1 Ensure that writes are enabled EECON2 0x55 Write sequence EECON2 0xaa EEWR 1 Start write operation while EEIF Wait for write to complete DataPtr Increment pointer to RAM EEADR Increment EEPROM address WREN 0 Disable writes AN731 DS00731A page 62 Preliminary 2000 Microchip Technology Inc void ReadIntEE char Addr char DataPtr char NumBytes This routine reads data from the internal EEPROM on the PIC16F8xx devices It is designed to read 1 byte up to 255 bytes Addr address in EEPROM to begin reading DataPtr address in RAM to write data that was read NumBytes number of bytes to read void ReadIntEE char Addr char DataPtr char NumBytes char i EEADR Addr Set address in EEPROM EEPGD 0 Select data EEPROM for i 0 i lt NumBytes i EERD
77. oads two new item names and prices that are then programmed into data EEPROM Since these are values that could change frequently the data EEPROM was used for nonvolatile storage of the infor mation due to the higher endurance The same meth ods presented here can be used in conjunction with the bootloader of AN732 to download new source code into FLASH program memory The data that is transferred between the client and the server has some handshaking built in Once the con nection is established the client waits for a response from the server The value of the data is not important only the response from the server so the buffer is emp tied without any processing of the information The cli ent now responds with an index number between 0 and 9 This index is used by the server to extract the next vending machine item names and prices out of a database The format of this data is where is the index value 0 9 The server will then respond with the new names and prices in the following format lt name1 gt lt name2 gt lt price1 gt lt price2 gt The tilde character is used to denote the start of the string Each of the names and prices is a null termi nated ASCII string and they are delimited using semi colons Once the client receives this information and updates the data EEPROM the connection with the server is terminated At this point the client must be reset through a MCLR Reset or by cycling the powe
78. om void Initializes I O pins for use as Master Mode I2C void init_ext_eeprom void output_float EEPROM_SCL output_float EEPROM_SDA 2000 Microchip Technology Inc Preliminary DS00731A page 33 AN731 void write_ext_eeprom long int address char data Writes the value in data to the address in address void write_ext_eeprom long int address char data set for 256Kbyte EEPROM char w_tmp i2c_start start bit i2c_write 0xa0 control byte i2c_write hi address Address high byte i2c_write address Address low byte i2c_write data data byte i2c_stop stop bit delay_ms 11 delay to allow write void read_ext_eeprom long int address Returns the 8 bit value in address char read_ext_eeprom long int address set for 256Kbyte EEPROM char data r_tmp i2c_start start bit i2c_write 0xa0 control byte i2c_write hi address address high byte i2c_write address address low byte i2c_start restart i2c_write 0xa1 control byte data i2c_read 0 read byte i2c_stop stop bit return data
79. ome software library routines to control and interact with the S 7600A Besides the data sheet there are manuals for exact protocol implemen tations software API for the developer s kit and exam ple source code available for download MODEM The last key ingredient is the communications medium used to connect to the Internet The type of medium selected is highly application dependent but can include Wireless Cellular Power Line Carrier POTS Standard telephone lines All of these mediums require some infrastructure to be in place before the embedded device can communi cate Both wireless and cellular transceivers require antennas to be placed in the surrounding area to pro vide the communication channel While most areas have some of this infrastructure in place there are areas that are not completely covered Everyone has probably experienced this with a cellular telephone at one time or another Power line carrier also requires infrastructure to be in place There has to be some sort of transceiver at the other end of the power lines that communicates with the embedded application This infrastructure for this technology does not currently have the widespread use that wireless or cellular offer and therefore the costs to build this infrastructure would be substantial The standard telephone lines are everywhere The telephone poles wiring relay sta tions etc are already in place The cost of building the
80. p_left void Dispenses from Item 1 on left side of LCD Shows item being dispensed and shows quantities void disp_left void Write_LCD_1 Display Item names on LCD lcd_putc n lcd_putc 0x00 lcd_putc 0x00 lcd_putc 0x00 lcd_putc KerPlunk Show item dispensed if Quan_1 If still have Item 1 Quan_1 decrement quantity if Quan_1 0 Show out if quantity 0 strcpy Price_1 Out delay_ms 1500 short delay Write_LCD_1 Display Item names on LCD void disp_right void Dispenses from Item 2 on right side of LCD Shows item being dispensed and shows quantities void disp_right void Write_LCD_1 Display Item names on LCD lcd_putc n KerPlunk Show item dispensed lcd_putc 0x00 lcd_putc 0x00 lcd_putc 0x00 if Quan_2 If still have Item 2 Quan_2 decrement quantity if Quan_2 0 Show out if quantity 0 strcpy Price_2 Out delay_ms 1500 short delay Write_LCD_1 Display Item names on LCD void Make_arrow void Creates a down arrow in User RAM on the LCD module
81. r It now switches back to the normal mode of operation using the new names and prices provided by the web server Other information such as total amount of money collected and the number of remaining items could have been transmitted back to the server but the application was kept simple for both the client and the server This interaction is highly application dependent and can be easily adapted based on the system requirements CONCLUSION The move to embed the Internet is creating many new and fascinating devices for all different types of mar kets Cellular phones and PDAs are the latest devices to add Internet capability Soon many household appli ances such as refrigerators will have Internet capabil ity and these embedded applications will dominate the Internet These devices can Internet enable any appli cation that has already used most of the available microcontroller resources to control the application In most cases a microcontroller cannot afford to dedicate 5 Kbytes of program memory and a significant portion of data memory for Internet connections This need has created devices such as the S 7600A and Si2400 spe cifically for the embedded Internet market FURTHER REFERENCE RFC1332 The PPP Internet Protocol Control Protocol RFC1334 PPP Authentication Protocols RFC1661 The Point to Point Protocol RFC1662 PPP in HDLC like Framing RFC1700 Assigned Numbers RFC793 TCP RFC821 SMTP RFC1725 POP3
82. r address char data Writes a byte of data to a register on the S 7600A void WriteSeiko char address char data while BUSY Wait for S 7600A CS 1 1st cycle sets register address RS 0 WRITEX 0 PORTD address Send address TRISD 0 READX 1 READX 0 WRITEX 1 RS 1 CS 0 CS 1 2nd cycle sends data WRITEX 0 PORTD data Send data READX 1 READX 0 WRITEX 1 CS 0 TRISD 0xff char ReadSeiko char address Reads a byte of data from a register on the S 7600A char ReadSeiko char address char data while BUSY Wait for S 7600A CS 1 1st cycle sets register address RS 0 WRITEX 0 PORTD address Write address TRISD 0 READX 1 READX 0 WRITEX 1 RS 1 CS 0 AN731 DS00731A page 58 Preliminary 2000 Microchip Technology Inc TRISD 0xff 2nd cycle CS 1 RS 0 READX 1 data PORTD READX 0 RS 1 CS 0 while BUSY Wait for S 7600A CS 1 to get data READX 1 data PORTD Read data READX 0 CS 0 return data char DataAvailable void Determines if there is any data available to read out of
83. r from USART CTS 1 disable send if index 32767 Stop if EEPROM is full break if ch 00 Stop if NULL is read break if ch Stop if semicolon is read break Otherwise write character to EEPROM write_ext_eeprom index ch FLASH status LED to indicate data transfer if bit_test index 4 flash LEDs LED1 1 LED2 0 else LED1 0 LED2 1 index write_ext_eeprom index 0 Write terminating NULL CTS 0 enable send LED1 1 turn off LEDs LED2 1 Print status of download to EEPROM index index 80 printf c 2J esc clear screen printf c 12 28H Received lu bytes esc index if index gt 32688 printf c 18 20H Error maximum bytes is 32688 esc printf c 18 25H Press any key to continue esc ch getc CTS 1 disable send 2000 Microchip Technology Inc Preliminary DS00731A page 23 AN731 void Write_data_to_rs232 void Debugging routine that dumps the contents of the EEPROM to the terminal Must uncomment line in main void Write_data_to_rs232 void Read and print username password and phone number for index 0 index lt 0x50 index ch read_ext_eeprom index temp isalnum ch if temp putc ch else putc Read out web page until a null
84. rom the UART When packets are received the TCP IP engine determines if the IP address and port number match those set during configuration calcu lates and verifies the checksums and transfers the data contents of the packet to a buffer It then uses interrupt lines to indicate there is data available to the microcontroller The complete list of features for the S 7600A are Implements PPP IP TCP UDP and PAP Two general purpose sockets Two parallel interfaces 68K x80 Motorola Intel MPU bus or synchronous serial interface On chip UART physical layer transport interface 256 kHz typical operating frequency Low power consumption 0 9 mA typical 1 0 A standby 2 4 V to 3 6 V operating voltage range The designer now has full Internet capabilities without any of the limitations of the software implementations The bulk of the program memory on the microcontroller can now be used for the main application and also for implementing some of the Application Layer protocols previously described The size of the program memory is now dependent on the application and can be scaled accordingly The S 7600A delivers Internet capability to the bulk of microcontrollers that were previously con strained due to program and data memory size The data sheet for the S 7600A can be downloaded from their website at http www seiko usa ecd com There is also a designer s kit available in the form of a PC card It includes s
85. rt WriteSeiko Socket_Index 0x00 Use socket 0 WriteSeiko Socket_Config_Status_L 0x10 Reset socket delay_ms 10 WriteSeiko Our_Port_L 80 open a socket to listen on port 80 WriteSeiko Our_Port_H 0 Reg 0x22 TCP server mode WriteSeiko Socket_Config_Status_L 0x06 Reg 0x24 General socket 0 active WriteSeiko Socket_Activate 0x01 delay_ms 5 Socket open wait for connection printf n rSocket open n r i 2 while 1 Check to see if PPP is still up or modem has disconnected delay_ms 1 if ReadSeiko PPP_Control_Status amp 0x01 gotorestart if ReadSeiko Serial_Port_Config amp 0x40 gotorestart Read socket status and process temp ReadSeiko Socket_Status_M if temp amp 0x10 set Connection established i 0 break else if temp amp 0xe0 Error detected break if temp 0x09 Waiting for connection continue by web browser delay_ms 5 i if i 255 Timeout 2000 Microchip Technology Inc Preliminary DS00731A page 29 AN731 break if i break if i 1 Timeout detected break printf n rWaiting for data WriteSeiko Socket_Interrupt_H 0xf0 Clear interrupt i 0 Read data send by web browser and dump to terminal printf n rReading data r n while ReadSeiko Socket_Config_Status_L amp 0x10 temp ReadSeiko Socket_Data putc temp Write HTTP Header which is nothing just termination for
86. s design in volume should be less than 9 00 AN731 DS00731A page 6 Preliminary 2000 Microchip Technology Inc After recovering from the size shock the impressive list of features makes this product a winner The list includes AT command set support V 21 Bell 103 V 22 Bell 212A V 22bis V 23 amp SIA support Caller ID detection and decode Call progress support Voice codec Globally programmable DAA FCC CTR21 NET4 JATE etc Parallel phone detect Wake up on ring Overcurrent detection Never before has the embedded control electronics industry seen a modem design this integrated AND this small AND this CHEAP But one question remains why 2400 baud Isn t that baud rate a little slow to use for Internet applications even embedded Internet applica tions The answer is quite simple If the application was a web server then yes a 2400 baud modem is not practical But it was already established that a web server was not practical for the embedded world A typ ical embedded application will only transfer several hundred bytes of data When looking at the complete connect and transfer time of one session a 2400 baud modem will connect in approximately three seconds and upload 200 bytes of data in 0 833 seconds 200 bytes x 10 bits byte x 1s 2400 bits for a total of 3 833 seconds A 56K modem will connect in approximately 15 seconds and transfer 200 bytes in 0 036 seconds 200 by
87. t PSPMODE TRISE 4 PIE1 Bits bit PSPIE PIE1 7 bit ADIE PIE1 6 bit RCIE PIE1 5 bit TXIE PIE1 4 bit SSPIE PIE1 3 bit CCP1IE PIE1 2 bit TMR2IE PIE1 1 bit TMR1IE PIE1 0 PIE2 Bits bit EEIE PIE2 4 bit BCLIE PIE2 3 bit CCP2IE PIE2 0 PCON Bits bit NOT_POR PCON 1 bit NOT_BOR PCON 0 SSPCON2 Bits bit GCEN SSPCON2 7 bit ACKSTAT SSPCON2 6 bit ACKDT SSPCON2 5 bit ACKEN SSPCON2 4 bit RCEN SSPCON2 3 bit PEN SSPCON2 2 2000 Microchip Technology Inc Preliminary DS00731A page 69 AN731 bit RSEN SSPCON2 1 bit SEN SSPCON2 0 SSPSTAT Bits bit SMP SSPSTAT 7 bit CKE SSPSTAT 6 bit D_A SSPSTAT 5 bit P SSPSTAT 4 bit S SSPSTAT 3 bit R_W SSPSTAT 2 bit UA SSPSTAT 1 bit BF SSPSTAT 0 TXSTA Bits bit CSRC TXSTA 7 bit TX9 TXSTA 6 bit TXEN TXSTA 5 bit SYNC TXSTA 4 bit BRGH TXSTA 2 bit TRMT TXSTA 1 bit TX9D TXSTA 0 ADCON1 Bits bit ADFM ADCON1 5 bit PCFG3 ADCON1 3 bit PCFG2 ADCON1 2 bit PCFG1 A
88. t buffer and wait WriteSeiko TCP_Data_Send 0 while ReadSeiko Socket_Status_H check if modem has disconnected if ReadSeiko Serial_Port_Config amp 0x40 gotorestart if bit_test PIR1 TMR1IF if this loops times out then count the socket has if count gt 0xf8 hung or the user has hit stop count1 count 0 if count1 gt 0xC0 goto restart bit_clear PIR1 TMR1IF clear interrupt flag LED2 0 Otherwise write data to socket WriteSeiko Socket_Data ch index We are done sending send the buffer of data WriteSeiko TCP_Data_Send 0 LED2 1 turn LED2 OFF Wait for socket to finish sending data count 0 bit_clear PIR1 TMR1IF clear interrupt flag while 0x40 ReadSeiko 0x22 amp 0x40 if bit_test PIR1 TMR1IF count bit_clear PIR1 TMR1IF clear interrupt flag Close Socket printf close socket n LED2 1 turn LED2 OFF WriteSeiko Socket_Activate 0 close the socket WriteSeiko TCP_Data_Send 0 Wait for Socket To Close 2 5 seconds Max can shorten in most cases if we ve waited for the buffer to empty above for i 0 i lt 255 i 2000 Microchip Technology Inc Preliminary DS00731A page 31 AN731 delay_ms 10 temp ReadSeiko Socket_Status_M if temp amp 0x0f 0x08 Socket closed break if temp amp 0xe0 Error detected break printf n rfinal socket wait n while Re
89. te WriteSeiko Clock_Div_H 0x01 Set Baud Rate Divisor for 2400 baud 9 828606 WriteSeiko BAUD_Rate_Div_L 0x7e WriteSeiko BAUD_Rate_Div_H 0x00 Set up MODEM printf S_Putc ATS07 06SE2 C0 r Send V22bis to modem delay_ms 10 printf S_Putc ATE0 r Send Local echo off delay_ms 10 WriteSeiko PPP_Control_Status 0x01 reset PPP WriteSeiko PPP_Control_Status 0x00 WriteSeiko PPP_Control_Status 0x20 set PAP mode delay_ms 5 Determine length of Username and write it to the PAP register in the S 7600A ReadIntEE 0 user 32 read 32 byte password from EEPROM address 0x00 i strlen user Find actual string length WriteSeiko PAP_String i Write string length to PAP register Write Username to PAP register in S 7600A for j 0 j lt i j WriteSeiko PAP_String user j Determine length of Password and write it to the PAP register ReadIntEE 0x20 pass 32 read 32 byte username from EEPROM address 0x20 i strlen pass Find actual string length WriteSeiko PAP_String i Write string length to PAP register Write Password to PAP register in S 7600A 2000 Microchip Technology Inc Preliminary DS00731A page 53 AN731 for j 0 j lt i j WriteSeiko PAP_String pass j WriteSeiko PAP_String 0x00 Write final NULL character to PAP register Read Phone Number from EEPROM ReadIntEE 0x40 phone 16 read 16 b
90. te CCP2CON 0x01D byte ADRESH 0x01E byte ADCON0 0x01F AN731 DS00731A page 36 Preliminary 2000 Microchip Technology Inc byte OPTION_REG 0x081 byte TRISA 0x085 byte TRISB 0x086 byte TRISC 0x087 byte TRISD 0x088 byte TRISE 0x089 byte PIE1 0x08C byte PIE2 0x08D byte PCON 0x08E byte SSPCON2 0x091 byte PR2 0x092 byte SSPADD 0x093 byte SSPSTAT 0x094 byte TXSTA 0x098 byte SPBRG 0x099 byte ADRESL 0x09E byte ADCON1 0x09F byte EEDATA 0x10C byte EEADR 0x10D byte EEDATH 0x10E byte EEADRH 0x10F byte EECON1 0x18C byte EECON2 0x18D STATUS Bits bit IRP STATUS 7 bit RP1 STATUS 6 bit RP0 STATUS 5 bit NOT_TO STATUS 4 bit NOT_PD STATUS 3 bit Z STATUS 2 bit DC STATUS 1 bit C STATUS 0 INTCON Bits bit GIE INTCON 7 bit PEIE INTCON 6 bit T0IE INTCON 5 bit INTE INTCON 4 bit RBIE INTCON 3 bit T0IF INTCON 2 bit INTF INTCON 1 bit RBIF INTCON 0 PIR1 Bits bit PSPIF PIR1 7 bit ADIF PIR1 6 bit RCIF PIR1 5 bit TXIF PIR1 4 bit SSPIF PIR1 3 bit CCP1IF PIR1 2 bit TMR2IF PIR1 1 bit TMR1IF PIR1 0 PIR2 Bits bit EEIF PIR2 4 bit BCLIF PIR2 3 bit CCP2IF PIR2 0 2000 Microchip T
91. tes x 10 bits byte x 1s 56000 bits This calcula tion shows that a 2400 baud modem can connect to the ISP dump the data to the server and disconnect before the 56K modem even establishes a connection to the modem on the other end of the line It just doesn t make sense especially when you consider the price of the 2400 baud modem versus the 56K modem Another feature of a telephone based system is choos ing the ISP to make the Internet connection Everyone hears about the high speed Internet links such as cable modems Most providers are targeting customers that want high speed access for web browsing According to the estimates this market which itself is very large will be dwarfed by the embedded devices Some com panies are starting to realize this fact and are catering towards these embedded applications with low speed modems One such company is iReady with their iready net service It caters to all facets of Internet con nectivity but includes the service for embedded low speed modem applications The data sheet for the Si2400 Si3015 can be down loaded from the Silicon Laboratories website at http www silabs com They also make a modem eval uation board that has a complete modem implementa tion and an RS 232 interface for use with a PC The user s manual for the evaluation board is also available from the website and provides some suggested layout guidelines FIGURE 3 MODEM SIZE COMPARISON Si2400 Typical Modem
92. the information If the machine is out of change full of deposited money or needs restocking a report can be generated detailing exactly what is required The service person can now make one trip to the machine because they know exactly what that particular machine needs The machine can also call out if an operating error has been detected This may include the vending machine is tilted to improperly dispense items or lights have burned out A service report is generated and the service person knows exactly what is needed to fix the problems Since we have established a full duplex link the embedded Internet connection can provide additional benefits such as reprogramming the microcontroller with new firmware to fix bugs or new pricing structure for items MICROCONTROLLER The microcontroller is the primary component of the application not necessarily a part of the Internet com munications In some cases it may be advantageous to offload the Internet communications to an external device so the microcontroller can focus on the details of the application as well as the application layer of the Internet Protocol Stack see Figure 2 FIGURE 2 INTERNET PROTOCOL STACK One feature that provides the most flexibility for an embedded application is FLASH based program mem ory FLASH program memory provides the capability to reprogram portions of the firmware remotely over the Internet connection The sections of firmware that can be
93. utine dumps all data stored in the EEPROM to the PC terminal it is used for debug only Main program starts here Waits for user input which is dispense one of the two items and update quantities or connect to server and get new information Main_loop LED1 1 LED OFF LED2 1 RESET 0 Reset modem and S 7600A delay_ms 1 RESET 1 Read_data Get data from Internal EEPROM and store it in variables Write_LCD_1 Display Item names on LCD Wait for user input while 1 ch bit_test PORTA 0 rest for call button if ch 0 Call button pressed break AN731 DS00731A page 52 Preliminary 2000 Microchip Technology Inc if Quan_1 If still have Item 1 ch bit_test PORTC 3 Left button pressed if ch 0 disp_left Dispense Item 1 if Quan_2 If still have Item 2 ch bit_test PORTC 4 Right buttonpressed if ch 0 disp_right Dispense Item 2 This part of the program makes the Internet connection to the server and retrieves the new information to store in the EEPROM restart LED1 1 LED OFF LED2 1 RESET 0 Reset modem and S 7600A delay_ms 1 RESET 1 lcd_putc fReseting Modem n printf n rReseting Modem delay_ms 10000 Set clock divider for 1KHz clock WriteSeiko Clock_Div_L 0x32 while ReadSeiko Clock_Div_L 0x32 Detects when reset WriteSeiko Clock_Div_L 0x32 is comple
94. utine to read out the contents of the internal EEPROM and dump it to the user s terminal 2000 Microchip Technology Inc Preliminary DS00731A page 63 AN731 void Get_username void Requests and reads the user name from the input terminal void Get_username void i 0 Print request to terminal printf c 2J esc printf c 12 20H 32 chars max esc printf c 10 20H Enter user name esc while 1 Read characters until a CR is read or 32 chars user i 0 have been read ch GETC if ch 0x0D break putc ch if ch 0x08 user i ch i if i 32 break write user name to the Internal EEPROM WriteIntEE 0 user 0x1f void Get_password void Requests and reads the password from the input terminal void Get_password void i 0 Print request to terminal printf c 2J esc printf c 12 20H 32 chars max esc printf c 10 20H Enter password esc while 1 Read characters until a CR is read or 16 chars pass i 0 have been read ch getc if ch 0x0D break if ch 0x0A l
95. x1d define Socket_Index 0x20 define Socket_TOS 0x21 define Socket_Config_Status_L 0x22 define Socket_Status_M 0x23 define Socket_Activate 0x24 define Socket_Interrupt 0x26 define Socket_Data_Avail 0x28 define Socket_Interrupt_Mask_L 0x2a define Socket_Interrupt_Mask_H 0x2b define Socket_Interrupt_L 0x2c define Socket_Interrupt_H 0x2d define Socket_Data 0x2e define TCP_Data_Send 0x30 define Buffer_Out_L 0x30 define Buffer_Out_H 0x31 define Buffer_In_L 0x32 define Buffer_In_H 0x33 define Urgent_Data_Pointer_L 0x34 define Urgent_Data_Pointer_H 0x35 define Their_Port_L 0x36 define Their_Port_H 0x37 define Our_Port_L 0x38 define Our_Port_H 0x39 define Socket_Status_H 0x3a define Their_IP_Address_L 0x3c define Their_IP_Address_M 0x3d define Their_IP_Address_H 0x3e define Their_IP_Address_U 0x3f define PPP_Control_Status 0x60 define PPP_Interrupt_Code 0x61 define PPP_Max_Retry 0x62 define PAP_String 0x64 2000 Microchip Technology Inc Preliminary DS00731A page 71 AN731 NOTES Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates It is your responsibility to ensure that your application meets with your specifications No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the a
96. yte Phone Number from EEPROM address 0x40 Send Phone Number to the MODEM printf S_Putc ATDT Send initial ATDT to indicate tone dial i strlen phone for j 0 j lt i j Write phone number to modem S_Putc phone j printf S_Putc r end with CR delay_ms 5 Also Write Phone Number to LCD lcd_putc fCall n Calling i 0 while phone i Write phone number lcd_putc phone i i Also Write Phone Number to CRT printf c 2J esc clear VT100 screen printf rDialing Write dialing printf phone Write phone number printf r LED1 0 LED ON Read status bytes from modem while dialing while 1 i ReadSeiko Serial_Port_Config Read UART status lcd_send_byte 0 0x87 goto first line char 8 if bit_test i 7 If data available ch ReadSeiko Serial_Port_Data read if ch t dial tone detected lcd_putc dial tone n printf ndial tone r if ch r ring detected lcd_putc ring printf nring r if ch c modem connected break done if ch b busy tone detected lcd_putc busy reset amp start over printf nbusy r gotorestart if ch l No phone line detected lcd_putc fNo Phone Line printf nNo Phone Line r lcd_putc nPRESS MCLR printf nPRESS MCLR r

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