QDS User`s Guide
Contents
1. It is recognized that suppliers of Part 15 transmitters often want their customers to be able to replace an antenna if it should break With this in mind Part 15 allows transmitters to be designed so that the user can replace a broken antenna When this is done the replacement antenna must be electrically identical to the antenna that was used to obtain FCC authorization for the transmitter The replacement antenna also must include the unique connector described above to ensure it is used with the proper transmitter Hobbyists inventors and other parties that design and build Part 15 transmitters with no intention of ever marketing them may construct and operate up to five such transmitters for their own personal use without having to obtain FCC equipment authorization If possible these transmitters should be tested for compliance with the Commission s rules If such testing is not practicable their designers and builders are required to employ good engineering practices in order to ensure compliance with the Part 15 standards 19 Home built transmitters like all Part 15 transmitters are not allowed to cause interference to licensed radio communications and must accept any interference that they receive If a home built Part 15 trans mitter does cause interference to licensed radio communications the Commission will require its opera tor to cease operation until the interference problem is corrected Furthermore if the Commission deter m2. widths range in binary steps from 0 625kHz to 5kHz SWP mode or 1 25kHz to 10kHz FIXED mode The user only needs to program the appropriate filter selection based on data rate and code modulation format 5 2 Reference Oscillator and External Timing Element All timing and tuning operations on the QwikRadio C are derived from the reference oscillator function This function is a singe pin Colpitts type oscillator The user may handle this pin in one of three possible ways Connect a ceramic resonator Connect a crystal Drive this pin with an external timing signal The third approach is attractive for further lowering system cost if an accurate reference signal exists elsewhere in the system e g a reference clock from a crystal or ceramic resonator based microproces sor and flexibility exists in the choice of system transmit frequency The user should AC couple this signal into the REFOSC pin and resistively divide or otherwise limit the signal to approximately 0 5Vpp A sinusoid is preferred and sharp transitions on this signal should be avoided to the extent possible 14 5 3 Slicing Level and the CTH Capacitor Extraction of the DC value of the demodulated signal for purposes of logic level data slicing is accom plished by external capacitor C TH and the on chip switched cap resistor R SC The effective resis tance of R SC varies in the same way as the demodulator filter bandwidth in four binary steps from approxima
3. Load working value for number of times to beep beepctr Move working value into beepctr register piezo Start high period of beep signal delayl Wait 98uS piezo Start low period of beep signal delayl Wait 98uS beepctr 1 One period is complete skip next line if beepctr is depleted bpi Repeat 5 1KHz beep routine J Load value for a wait period between high and low frequency beeps dly2 Call delay routine Generate 4KHz Tone 122 Load working value for number of times to beep beepctr Move working value into beepctr register piezo Start high period of beep signal delay2 Wait 124uS piezo Start low period of beep signal delay2 Wait 124uS beepctr 1 One period is complete skip next line of beepctr is depleted bp2 Repeat 4KHz beep routine 25 De Wait1Bit repeatl repeat2 i lt ByteDelay repeat3 repeat4 repeat5 Delay sx WaitHalfBit repeat6 delayl dli decfsz repeat f Decrease repeat register and skip if zero goto Tonel Repeat beep signal return Return from beep routine lay routine for waiting one bit period 833uS 1200 baud movlw d 255 Load constant into working for counti movwf counti Load working into counti register decfsz countl1 f Decrease countl and skip when counter equals zero goto repeatl Repeat until counter equals zero moviw d 22 Load constant into working for count2 movwf count2 Load working into count2 register d
4. Section All QDS s are supplied with an on board 4 MHz flash based microcontroller MCU It can be repro grammed up to 10 000 times with an inexpensive programmer The MCU comes pre programmed with sample code which allows the user to transmit and receive simple asyncronous protocol with its corre sponding QDS unit The sample code can be modified in an ASCII editor and reprogrammed according to the requirements of the user s application The MCU is connected to the receiver s data output wake up and power down features as well as the transmitter s data input two LEDs a piezo element and one relay The MCU comes pre programmed with embedded firmware and software which supports simple asyncronous communication between both QDS development boards The sample code includes a basic method for preemption detection LED and relay activation as well as a warbling beep routine to drive the on board piezo element 3 5 Antenna Options and Interfaces The QwikRadio s antenna input can be matched to a number of external antennas by using the L inductor network provided on the development unit The QDS allows for two antenna polarizations and several different antenna types such as monopole whip helical helically loaded whips and others There are two antenna feed ports horizontal SMA and direct PCB mount via the on board jack The units a shipped with two monopole whip antennas which are inserted directly into the transmit and
5. System Limitations The QwikRadio Development System QDS is intended for use by engineers for the purpose of evaluating the feasibility of implementing the QwikRadio series of Micrel s RF IC s in various wire less applications The user s environment must be limited to use of the development system within an environment which provides for adequate isolation of RF emissions which might be caused by operation of the QDS In field testing the device must not be operated in a residential area or any area where radio devices might be subject to harmful electrical interference The development system has not been certi fied for use by the FCC in accord with Part 15 ETSI I ETS 300 220 or I ETS 300 220 1 regulations or other known standards of operation governing radio emissions Distribution and sale of the QDS is intended solely for use in future development of devices which may be subject to FCC regulation or other authorities governing radio emission QDS may not be resold by users for any purpose Accord ingly operation of the QDS in the development of future devices is deemed within the discretion of the user and the user shall have all responsibility for any compliance with any FCC regulation or other authority governing radio emissions of such development or use including without limitation reducing electrical interference to legally acceptable levels All products developed by user must be approved by the FCC or other authority gov
6. bit is low zero Test bit Clear carry if incoming bit is high one Rotate carry into RxByte Decrease counter skip if all 8 bits have been received Get more bits Shift to stop bit low before looking for next start bit Return with received byte in RxByte 24 i lt SendByte NextBit Continue Beep Tonel bpl Tone2 bp2 movilw movwEt bsf call rrf btfss bcf btfsc bsf call decfsz goto bcf call call Serial Data TX Routine return moviw movwf movlw movwf bsf call bcf call decfsz goto movilw call movlw movwf bsf call bcf call decfsz goto Enter routine with byte to transmit in txbyte 0x08 BitCntr Load bit counter for 8 data bits txdata Begin start bit High WaitlBit Wait one bit length txbyte 1 Rotate TxByte out to carry status C Test carry skip if set txdata Clear output pin for logical low zero Status c Test carry skip if set txdata Set output pin for logical high one WaitlBit Wait one bit length BrtCntr 1 Decrease bit counter amp skip if zero Result gt register NextBit no more bits so jump and do stop bits txdata Begin stop bit Wait1Bit Wait 1 stop bit WaitlBit Wait 1 stop bit total 2 stop bits Warble Beep Routine 0x05 Repeat Warble x times repeat Move constant to repeat register Generate 5 1KHz Tone 153
7. is designed to be connected to a quarter wave monopole antenna at its input ANT pin with no further coupling network and provide this similar range Of course the monopole can be a free standing wire or a metal trace built directly into the pcb The antenna need not be a quarter wavelength long but shorter lengths will reduce range Although the other two antenna types helical and pcb loop are less efficient antennas than the monopole they provide cost and or ergonomic advantages The pcb loop antenna is a very inexpensive structure to produce being built into the pcb The only requirement is that there be enough room on the pcb to build a sufficiently effective antenna This antenna has the further advantage that it can be hidden from the end user The primary disadvantage is that this is usually the least efficient of the three antenna types being discussed with a typical range of 30 meters Loop antennas are more commonly found in transmitters than receivers Where the antenna must be hidden but still be rather efficient a good choice is the helical antenna The structure is simply a coil of wire inexpensive and easy to fabricate Typical range for this type of antenna is 60 meters Both helical and pcb loop antennas are commonly found in transmitter designs which usually requires a small unit with the antenna hidden from the user Another aspect of antenna selection aside from its effec tiveness at picking up signa
8. receive antenna ports Figure 1 3 6 RS 232 Interface The Windows based software supplied with the QDS package permits the users to communicate PC to PC where both QDS units are connected via their RS232 port and the associated jumpers are appropri ately placed 3 7 Breadboard Area The development board offers a prototype area with several 0 100 spaced vias There are also VCC and GND rails provided at the top and bottom of this section 3 8 Receiver Section The receiver section is the core of the development system and the primary purpose for its use The receiver area includes one QwikRadio RFIC which comes with a factory preset frequency 10 The reference frequency can also be generated by an alternate crystal oscillator in the receiver section Figure 1 The user must populate and calibrate the alternate oscillator as it does not come pre installed from the factory All QwikRadio series chips allow the user to select between different baud rates and either a scanning or fixed local oscillator LO The development board allows the user to quickly and easily reconfigure these settings by the placement or removal of shorting jumpers In addition the units provide two different automatic gain control AGC configurable settings positive and ground bias Several different data slicer reference configurations are also possible integrator capacitor voltage reference divider and variable among others 3 9 Transmitter Section
9. Contains byte to transmit upon entry into SendByte routine Contains received byte from Receiver Temporary storage of data to transmit Counter for number of times to repeat beep subroutine Counter for misc delay routines Counter for misc delay routines Counter for misc delay routines Counter for Dlyl and Dly2 routines PR RR KRRKRKKRE RRR KEK kkk kkk kkk ke ke he kkk KEK KKK kk kkk RK KKK KEKE RK kc k kk k k k kk k k k kk k k k ko k k ORG 0x000 Processor reset vector goto Init Go to beginning of program lt Check button depression checkbutton btfsc button2 Test button2 skip next line if depressed return Return from subroutine call SendBurst Send data burst return Return from subroutine P GetByte Receive Routine Received byte is in RXByte on exit GetByte movlw 0x08 movwf BitCntr TestInput btfss rxdata goto TestInput InputHigh call WaitHalfBit btfss rxdata goto TestInput GetBits call Wait1Bit btfss rxdata bcf status c btfsc rxdata bsf status c rtf RxByte 1 decfsz BitCntr 1 goto GetBits call Wait1Bit return Load bit counter for 8 data bits Look for start bit high skip if true loop if no data detected Wait one half of one bit length Check start bit again Loop if no data detected Wait one bit length Test bit condition Set carry if incoming
10. IMITATION ANY CLAIMS DAMAGES OR LIABILITIES FOR LOSS OF BUSINESS PROFITS BUSINESS INTERRUPTION LOSS OF BUSINESS INFOR MATION OR FOR INJURY TO PERSON OR PROPERTY ARISING OUT OF THE USE OR IN ABILITY TO USE THE QDS EVEN IF RFL HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES BECAUSE SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITA TION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES THE ABOVE LIMITATION MAY NOT APPLY TO YOU 1 QwikRadio Development System Introduction 1 1 General Description The QwikRadio Development System comprises the hardware firmware and software resources commonly used by wireless designers in the design and development of wireless applications The QwikRadio Development System QDS offers a comprehensive test suite that allows the developer designer to vary a number of electrical firmware software and antenna parameters to facilitate the optimal architecture and topology for the given application being developed 1 2 Intended User The QwikRadio Development System QDS is intended for use solely by engineers for the purpose of evaluating the feasibility of implementing the QwikRadio series of Micrel s RF IC s in various wireless applications The user s evaluation must be limited to use of the development system within a environment which provides for adequate isolation of RF emissions which might be caused by operation of the QDS In field testing the device must not be ope
11. O on internal instruction cycle DISABLE pull ups bcf status rpO Switch back to bank 0 movlw B 00000000 DISABLE ALL INTERRUPTS moviw B 10001000 Enable global interrupts enable rb4 rb7 pin change movwf intcon Load working value into interrupt register bcf relay Turn OFF relay bcf ledi Turn OFF led1 bcf led2 Turn OFF led2 bcf piezo Turn OFF piezo bcf txdata Set Data low normal state clrf Countl jInitialization of delay counter by clearing clrf Count2 jInitialization of delay counter by clearing clrf Count3 jInitialization of delay counter by clearing clrf MS Tim jInitialization of delay counter by clearing goto Start Go to main program END 29
12. QDS QwikRadio Development System User s Guide Covers the follow parts DS QDS 315 DS QDS 418 DS QDS 433 DS QDS 915 RF Laboratories Inc QwikRadio Development System User s Guide Table of Contents QwikRadio Development System Limitations QwikRadio Development System Warranty 1 QwikRadio Development System Introduction 1 1 General Description 1 2 Intended User 2 Getting Started 2 1 QDS diagram 2 2 Quickstart instructions 3 Assembly and QDS Overview 3 1 Assembly of Development System 3 2 Jumpers and DIP Settings 3 3 Power Supply and Regulation 3 4 Microcontroller MCU Section 3 5 Antenna Options and Interfaces 3 6 RS 232 Interface 3 7 Breadboard Area 3 8 Receiver Section 3 9 Transmitter Section 4 Operation Instructions and Guidelines 4 Theory of Operation 4 2 I O Interface 4 3 LED Piezo and Button Functions 4 4 Microcontroller Protocol 4 5 RS232 Interface and Windows Software 5 Developing Applications with Micrel s QwikRadio IC s 5 1 A QwikRadio Overview 5 2 Reference Oscillator and External Timing Element 5 3 Slicing Level and the CTH Capacitor 5 4 AGC Function and the AGC Capacitor 5 5 Antenna Design Considerations 5 6 Bandwidth and Data Rate 5 7 Noise Management 6 Low power Radios and Regulatory Compliance 6 1 Electromagnetic Compliance 6 2 A Regulatory Overview 7 FAQ s 8 Sample Firmware 9 QDS Diagram 10 Data Sheets and Application Notes QwikRadio Development
13. QwikRadio IC in an opti mal bias for reception of the first byte of data The protocol in hexadecimal is as follows FF 00 F5 AA AA 12 4 5 RS232 Interface and Windows Software Installation Insert QDS CD into PC and navigate to QDS Windows Software Installation Files setup exe Follow all prompts and repeat process for other PC to be used in test The RS232 port is located to the rear of the both units Figure 1 RS232 Port After installing the QDS development software and determining which serial communication port is free for use connect a nine pin serial cable between the QDS RS232 port and the PC s serial communication port To open the QDS software go to the Windows start menu and after going into programs scroll down to QwikRadio Development System Before starting your testing it is necessary to designate a commu nications port from the scroll down menu labelled Comm Port to the right of the File menu Next a baud rate must be assigned in the next menu tab to the right The baud rates for both sides of the QDS system must match each other in order for the units to communicate The last menu bar is to execute a clear screen function which clears the receive data screen of all of its contents The preamble section in the lower left hand corner of the QDS software window contains two user definable bytes that can be modified to experiment with comparator bias levels which are necessary to optim
14. The development system board includes a transmitter which can be used to test the receiver portion of the system if other external transmitters or signal generators are not available The on board transmitter s frequency modulation and baud rate are all set to match the default configuration of the receiver as shipped from the factory 11 4 Operation Instructions and Guidelines 4 1 Theory of Operation The QDS system employs one receiver and one transmitter per unit Transmission and reception of wireless data is controlled in one of three ways by microprocessor RS232 PC or external hardware mounted in the prototyping area The development boards ship with microprocessor control as their default setting After applying power the asyncronous preemption can the initiated by the depression of SW2 the yellow momentary button The data packet is a simple three byte word preceded by a two byte preamble to place the comparator threshold of the QwikRadio IC in at optimal bias for reception of the first byte of data As the QwikRadio receiver IC demodulates the received data from the transmitter the IC s data output is sent to either the MCU RS232 or breadboard for processing If the MCU is interfaced to the RFIC the sample firmware will acknowledge a valid data packet by responding with a beep blink an LED once and finally toggle the on board relay between states If both QDS boards are jumpered to the RS232 interface and connected t
15. byte into working working into TxByte register second preamble byte first header working into first header address working address byte into byte address working address byte into byte byte TxBy byte 0 in TxBy 0 1 in TxBy 1 with SendBurst r into working te register to working te register to working te register eturn to Start data receive routine Load constant into working for RxByte Subtract working from RxByte Skip if subtraction set zero flag high Check button 2 status for depression Call data receive routine for next byte Load first address byte into working Subtract working from RxByte Skip if subtraction set zero flag high Check button 2 status for depression Call data receive routine for next byte Load second address byte into working Subtract working for RxByte Skip if subtraction set zero flag high Check button 2 status for depression Beep once when good data is received Check button 2 for depression Go back to start and do it all over again 28 lt Init Ins amp Outs Init bsf status rpO Select bank 1 moviw B 11110000 jInitialize port a 0 output 1 input movwf TRISA Load working value into tris register moviw B 11111001 jInitialize port b 0 output 1 input movwf TRISB Load working value into tris register movlw B 10001000 Prescale assigned to WDT 1 1 movwf option reg TMR
16. ched an FCC ID label and a compliance label The FCC ID label identi fies the FCC equipment authorization file that is associated with the transmitter and serves as an indica tion to consumers that the transmitter has been authorized by the FCC The compliance label indicates to consumers that the transmitter was authorized under Part 15 of the FCC rules and that it may not cause nor is it protected from harmful interference The FCC ID The FCC ID must be permanently marked etched engraved indelibly printed etc either directly on the transmitter or on a tag that is perma nently affixed riveted welded glued etc to it The FCC ID label must be readily visible to the purchaser at the time of purchase The FCC ID is a string of 4 to 17 characters It may contain any combination of capital letters numbers or the dash hyphen character Characters 4 through 17 may be designated as desired by the applicant The first three characters however are the grantee code a code assigned by the FCC to each particu lar applicant grantee Any application filed with the FCC must have an FCC ID that begins with an assigned grantee code The Grantee Code To obtain a code new applicants must send in a letter stating the applicant s name and address and requesting a grantee code This letter must be accompanied by a completed Fee Advice Form FCC Form 159 and a 45 processing fee The Compliance Label The applicant for a grant of cer
17. deral Regulations Manufacturers and parties selling low power non licensed transmitters or products containing low power non licensed transmitters are strongly encouraged to review the FCC s regulations closely Recognizing that new uses of low power transmitters often generate questions that are not directly addressed in the regulations we welcome inquiries or requests for specific interpretations Occasionally the FCC proposes changes to its regulations generally to address industry concerns and or as new uses of low power transmission equipment appear 18 The terms low power transmitter low power non licensed transmitter and Part 15 transmitter all refer to the same thing a low power non licensed transmitter that complies with the regulations in Part 15 of the FCC rules Part 15 transmitters use very little power most of them less than a milliwatt They are non licensed because their operators are not required to obtain a license from the FCC to use them Although an operator does not have to obtain a license to use a Part 15 transmitter the transmitter itself is required to have an FCC authorization before it can be legally marketed in the United States This authorization requirement helps ensure that Part 15 transmitters comply with the Commission s techni cal standards and thus are capable of being operated with little potential for causing interference to authorized radio communications If a Part 15 tra
18. e performed on the transmitter to be authorized using a laboratory that has calibrated its test site or if the transmitter is incapable of being tested at a laboratory at the installation site These tests measure the levels of radio frequency energy that are radiated by the transmitter into the open air or conducted by the transmitter onto the power lines After these tests are performed a report must be produced showing the test procedure the test results and some additional information about the transmitter including design drawings Once the report is completed the manufacturer or importer for an imported device is required to keep a copy of it on file as evidence that the transmitter meets the technical standards in Part 15 The manufac turer importer must be able to produce this report on short notice should the FCC ever request it The manufacturer or importer is responsible for having the compliance label produced and for having it affixed to each transmitter that is marketed or imported Verified transmitters must be uniquely identi fied with a brand name and or model number that cannot be confused with other electrically different transmitters on themarket However they may not be labelled with an FCC ID or in a manner that could be confused with an FCC ID Once the report showing compliance is in the manufacturer s or importer s files and the compliance label has been attached to the transmitter marketing of the transmitter
19. e respective inc file See respective data sheet for additional information on configuration word Define Ports Define relay porta 0 Relay controller pin output Define txdata porta 1 Output pin for transmitting data output Define piezo porta 2 Piezo pin for controlling beeper output Define led2 porta 3 Led2 power pin output Define led1 porta 4 Ledi power pin output Define rxdata portb 0 Data input pin for recieving data input Define fetsw portb 1 Control pin for switching MOSFET in receiver section Define rxsdn portb 2 Shut down control pin for QwikRadio receiver output Define rxwup portb 3 Wake up input pin from receiver input Define buttonl portb 4 Input from button one depressed low Define button2 portb 5 Input from button two depressed low Define dipl portb 6 Input from DIP one On low Define dip2 portb 7 Input from DIP two On low 23 variables temp equ OxOC tempstatus equ OxOD templi equ OxOE temp2 equ OxOF beepctr equ 0x10 bitCntr equ 0x11 TXByte equ 0x12 RXByte equ 0x13 TempData equ 0x14 repeat equ 0x15 counti equ 0x16 count2 equ 0x17 count3 equ 0x18 MS Tim equ 0x19 Temporary storage of W Temporary storage of status reg Delay constant value for beep subroutine Delay constant value for beep subroutine Counter for length of each tone for multitonal beep subroutine Counter for tracking how many bits have been sent or received
20. ecfsz count2 f Decrease count2 and skip when counter equals zero goto repeat2 Repeat until counter equals zero return Return from delay routine Pre interbyte delay of 2 0 mS movlw d 255 Load constant into working for counti movwf counti Load working into counti register decfsz counti f Decrease countl and skip when counter equals zero goto repeat3 Repeat until counter equals zero movlw d 255 Load constant into working for count2 movwf count2 Load working into count2 register decfsz count2 f Decrease countl and skip when counter equals zero goto repeat4 Repeat until counter equals zero movlw d 155 Load constant into working for count3 movwf count3 Load working into count3 register decfsz count3 f Decrease count3 and skip when counter equals zero goto repeats Repeat until counter equals zero return Return from delay routine routine for waiting one half a bit period 416uS 1200 baud E movlw d 138 Load constant into working for count3 movwf count3 Load working into count3 register decfsz count3 f Decrease count3 and skip when counter equals zero goto repeat Repeat until counter equals zero return Return from delay routine 98uS delay clrf templ Clear templ register moviw 32 Load constant into working for templ movwf tempi Load working into tempi register decfsz templ1 1 Decrease templ and skip when counter equals zero goto dll Repeat until counter
21. equals zero return Return from delay routine 26 delay2 d12 Dlyl ttlloop ttloop i lt 124uS delay clrf templ moviw 41 movwf tempi decfsz templ1 1 goto dl2 return Delay Routine approx clrf Count1i moviw 100 movwf MS Tim moviw 6 movwf Count2 decfsz Countl f goto ttloop decfsz Count2 f goto ttloop decfsz MS Tim f goto ttlloop return Delay Routine Clear templ register Load constant into working for templ Load working into tempi register Decrease templ and skip when counter equals zero Repeat until counter equals zero Return from delay routine 1 2 sec Clear counter for this routine other counters are being loaded Load MS Tim register with constant for 1 2 sec Load working into MS Tim register Load constant into working for Count2 Load working into Count2 register Countl1 becomes OxFF on first decrement Repeat until Countli equals zero Decrease secondary counter Repeat until Count2 equals zero Decrease MS Tim counter and skip when counter equals zero Repeat until MS Tim equals zero Return from delay routine Dly enters with a number in MS Timer and delays in increments of this number times 6FFH to give delays in increments of 5 milliseconds set at approx 5 Msec delay Uses Countl Count2 MS Timer Dly2 ttloop3 ttloop2 clrf Countl movwf MS Tim movlw d 6 movwt Count2 decfsz Countl f goto ttloop2 decfsz C
22. erning radio emission prior to marketing or sale of such products and user bears all responsibility for obtaining the FCC s prior approval or approval as needed from any other authority governing radio emissions QDS is an experimental device and RF Laboratories Inc RFL makes no representation with respect to the adequacy of the QDS in developing low power wireless data communications applications or systems nor for the adequacy of such design or result RFL does not and cannot warrant that the func tioning of the QDS will be uninterrupted or error free The QDS and products based on the technology in the QDS operate on shared radio channels Radio interference can occur in any place at any time and thus the communications link may not be absolutely reliable Products using the QwikRadio technology must be designed so that a loss of communications due to radio interference or otherwise will not endanger either people or property and will not cause the loss of valuable data RFL assumes no liability for the performance of products which are designed or created using the QDS RFL s products are not suitable for use in life support applications biological hazard applications nuclear control applications or radioactive areas QwikRadio Development System Warranty RF Laboratories Inc RFL warrants solely to the purchaser that the hardware components of the QwikRadio Development System QDS will be free from defects in
23. ines that the operator of such a transmitter has not attempted to ensure compliance with the Part 15 technical standards by employing good engineering practices then that operator may be fined up to 10 000 for each violation and 75 000 for a repeat or continuing violation Operating a prototype of a product that is ultimately intended for market is not considered personal use Thus a party that designs and builds a transmitter with plans to mass produce and market a future version of it must obtain an experimental license from the FCC in order to operate the transmitter for any purpose other than testing for compliance with the Part 15 technical standards A Part 15 transmitter must be tested and authorized before it may be marketed There are two ways to obtain authorization certification and verification The certification procedure requires that tests be performed to measure the levels of radio frequency energy that are radiated by the device into the open air or conducted by the device onto the power lines A description of the measurement facilities of the laboratory where these tests are performed must be on file with the Commission s laboratory or must accompany the certification application After these tests have been performed a report must be produced showing the test procedure the test results and some additional information about the device including design drawings Certified transmitters also are required to have two labels atta
24. ize for best reception of the first data byte of the transmitted data packet The three header bytes can be used for redundancy or as address bytes They will along with the pre amble bytes be transmitted with every packet It is necessary that the header bytes match each other in both QDS software windows The software also facilitates a checksum feature which is activated by selection of the Checksum radial box The final feature of the program is an auto transmit switch which causes the last entered data packet to be re transmitted continuously After all of the above settings have been determined set and are matching in both QDS software win dows testing may begin by simply typing any text into the lower window label Transmit Data There after each depression of the Send button will cause the current data in the Transmit Data window to be transmitted once If user desired to experiment with different baud rates care must be taken that the QwikRadio receiver IC bandwidth settings match the data rates used in the QDS software 13 5 Developing Applications with Micrel s QwikRadio IC s 5 1 A QwikRadio Overview The QwikRadio series RF IC s are single chip OOK ON OFF Keyed receiver IC for remote wireless applications employing Micrel s QwikRadio technology All RF and IF tuning is accomplished automatically within the IC which eliminates manual tuning and reduces production costs Receiver func
25. l from the ether is its directionality Every type of antenna has its own signature of energy distribution in the 3 dimensional space that surrounds it This signature is generally composed of peaks and nulls if the transmit antenna peak is pointed at the receiving antenna s peak then range is maximized However optimizing this for a particular application or installation is generally not practical All one can do in these cases is choose the antenna that meets the other con straints like cost and form factor then test to determine if the system provides adequate range in all the required directions and orientations Unfortunately much of this work is empirical 15 Antenna types are described above without any special coupling circuits required However Micrel does recommend some sort of DC path be provided from the ANT pin to VSSRF This could be pro vided by an LC filter attached from the ANT pin to VSSRF or simply a resistor The ANT input is internally AC coupled so no external biasing is required The input circuit impedance is very high i e a FET gate shunted by approximately 2pF of parasitic capacitance giving an input AC impedance of about 200 Q at 400MHz Specialized 50 Q antennas may also be connected directly to the MICRFOOI The antenna should be connected as closely as possible to the IC pin minimizing parasitic inductance between the antenna pad and the pin Use a gt 25mil trace lt 200mil l
26. materials and workmanship under normal use for a period of 90 days from the date of shipment by RFL This limited warranty does not extend to any components or circuits which have been subjected to modification misuse neglect accident or improper installation or application RFL s entire liability and the purchaser s sole and exclusive remedy for the breach of this Limited Hardware Warranty shall be at RFL s option when accompanied by a valid receipt either 1 repair or replacement of the defective components or ii upon return of the defective QDS refund of the purchase price paid for the QDS EXCEPT FOR THE LIM ITED HARDWARE WARRANTY SET FORTH ABOVE RFL AND ITS LICENSORS PROVIDE THE HARDWARE ON AN AS IS BASIS AND WITHOUT WARRANTY OF ANY KIND EI THER EXPRESS IMPLIED OR STATUTORY INCLUDING BUT NOT LIMITED TO THE IM PLIED WARRANTIES OF NONINFRINGEMENT MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE Some states do not allow the exclusion of implied warranties so the above exclusion may not apply to you This warranty gives you specific legal rights and you may also have other rights which vary from state to state Limitation of liability IN NO EVENT SHALL RFL OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHETHER SPECIAL INCIDENTAL CONSEQUENTIAL OR OTHERWISE IN EXCESS OF THE PRICE ACTUALLY PAID BY YOU TO RFL FOR THE QDS REGARDLESS OF UNDER WHAT LEGAL THEORY TORT OR CONTRACT SUCH DAMAGES MAY BE AL LEGED INCLUDING WITHOUT L
27. may begin There is no filing with the FCC required for verified equipment Any equipment that connects to the public switched telephone network such as a cordless telephone is also subject to regulations in Part 68 of the FCC Rules and must be registered by the FCC prior to marketing The rules in Part 68 are designed to protect against harm to the telephone network 21 6 4 FAQ s 22 QDS Sample Firmware I f kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk Filename QDS asm Date 11 28 01 File Version A Author Engineering Company RF Laboratories pikk kkkkk kkk kkk kkk kkk kkk kkk kkk kkk kkk k kkk kkk kkk kk kkk k k kkk k k kkk k kk kk k k k k p16F84A inc pikk kkkkk kkk kkk kkk kkk kkk kkk kkk kkk kkk kk kkk kk kkk kk kkk k k kkk k k kkk k kk kk k k k k f 1 f f Files required Notes Sample asyncronous communication code for Quikradio Development System kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkxk list p 16F84A List directive to define processor include lt p16F84A inc gt Processor specific variable definitions __ CONFIG CP OFF amp _WDT_OFF amp _PWRTE_ON amp XT OSC Configuration directive CONFIG directive is used to embed configuration data within asm file The lables following the directive are located in th
28. nsmitter does cause interference to authorized radio communications even if the transmit ter complies with all of the technical standards and equipment authorization requirements in the FCC rules then its operator will be required to cease operation at least until the interference problem is corrected Part 15 transmitters receive no regulatory protection from interference Changing the antenna on a transmitter can significantly increase or decrease the strength of the signal that is ultimately transmitted Except for cable locating equipment the standards in Part 15 are not based solely on output power but also take into account the antenna characteristics Thus a low power trans mitter that complies with the technical standards in Part 15 with a particular antenna attached can exceed the Part 15 standards if a different antenna is attached Should this happen it could pose a serious inter ference problem to authorized radio communications such as emergency broadcast and air traffic control communications In order to prevent such interference problems each Part 15 transmitter must be designed to ensure that no type of antenna can be used with it other than the one used to demonstrate compliance with the technical standards This means that Part 15 transmitters must have permanently attached antennas or detachable antennas with unique connectors A unique connector is one that is not of a standard type found in electronic supply stores
29. o a PC with the QDS development software via a serial cable the RFIC s data output will be shown in the software received data display screen The units come with two monopole antennas which employ the ground plane of the QDS board itself as a reference The socket the antennas use will also accept other antennas with diameters between 0 048 0 064 Located on the edge of the receiver side of the units Figure 1 Receiver Antenna Jack is an SMA edge connector footprint intended for future installation of an SMA connector in the event the user desires to supply a signal to the QwikRadio receiver from another signal source 4 2 I O Interface The QDS boards are provided with one RS232 port one relay output and one SMA edge connector footprint 4 3 LED Piezo and Button Functions The development system is shipped with the microprocessor jumpered such that a depression the yellow button on the left side of the QDS will prompt the transmission of one data packet The LED will light also to indicate that a transmission did indeed occur The piezo element in turn is prompted to warble as an indication of a valid reception of one data packet 4 4 Microcontroller Protocol The microcontroller is preprogrammed with a simple asynchronous protocol intended to serve as a starting point for those unfamiliar with wireless data transmission It consists of a three byte word preceded by a two byte preamble to place the comparator threshold of the
30. o microcontroller 3 Install 9 volt battery in holder underneath each development board 4 Install two monopole antennas per unit into PCB mounted jacks indicated by Receiver Antenna Jack and Transmitter Antenna Jack in Figure 1 5 Turn power switch to the ON position and you are ready to test 3 Assembly and QDS Overview 3 1 Assembly of Development System The QwikRadio Development System comes assembled in a default configuration for immediate evaluation except for battery and antenna installations 3 2 Jumpers and DIP Settings The ODS units are shipped with the following default jumper settings ON MEANS THAT JUMPER IS INSERTED OFF MEANS THAT IT IS NOT JUMPER BUS RECEIVER CONFIGURATION SETTINGS RXDATA gt MCU ON SELO ON RXDATA gt 232 OFF SWEN ON RXDATA gt BB OFF SELI ON RXWUP MCU ON SDN ON RXWUP gt BB OFF RXSDN MCU ON RXSDN BB OFF RELAY gt MCU ON RELAY gt MCU OFF FETSW gt MCU ON FETSW gt BB OFF TXDATA gt MCU ON TXDATA gt 232 OFF TXDATA gt BB OFF 5V gt RXPWR ON 5V gt TXPWR ON 5V gt 232PWR OFF The settings may be modified after the demands of the respective application 3 3 Power Supply and Regulation The QDS units are power by a 9 volt alkaline cell and regulated with a industry standard 7805 voltage regulator The board s VCC VDD is therefore 5 volts 3 4 Microcontroller MCU
31. ong if possible The antenna can be located away from the pin of the device but this requires using a transmission line from the antenna to the IC input pin and an impedance matching coupling circuit Micrel does not recommend such an approach for users who lack the necessary RF expertise and test equipment to design transmission line matching networks Suitable antennas are crucial to the success the application Here are several key points to consider in designing antennas for your application Where possible the antenna should be placed on the outside of the product Also try to place the an tenna on the top of the product If the product is body worn try to get the antenna away for the body as far as practical Regulatory agencies prefer antennas that are permanently fixed to the product Antennas can be supplied with a cable provided a non standard connector is used to discourage antenna substitution these con nectors are often referred to as Part 15 connectors An antenna can not be placed inside a metal case as the case will shield it Also some plastics and coatings significantly attenuate RF signals and these materials should not be used for product cases if the antenna is going to be inside the case The antenna designs used in the kit are included in the Draw ings section of the manual Many other antenna designs are possible but efficient antenna development requires access to antenna test equipment such as a vect
32. or network analyzer calibrated test antenna antenna range etc Unless you have access to this type of equipment the use of an antenna consultant is recommended A patch or slot antenna can be used in some applications where an external antenna would be subject to damage These types of antennas usually have to be designed on a case by case basis 5 6 Bandwidth and Data Rate The inputs SWEN SELO and SEL control the operating mode and selectable features of the IC These inputs are CMOS compatible and are pulled up on the IC The inputs SELO and SEL control the Demodulator filter bandwidth in four binary steps 625Hz 5000Hz in SWP 1250Hz 10000Hz in FIXED mode and the user must select the bandwidth appropriate to his needs 16 5 7 Noise Management Noise sources are found in all places and at all times So the real question regarding noise generation and management is not IF but how much what frequency and at what amplitude Radios which operate under FCC Part 15 guidelines are subject to noise like any other receiver Some noise sources com monly encountered by wireless developers are microprocessors motors or fans high frequency logic circuits among others When there exist sufficient speed regarding the rise time and fall time of micro processor clocks harmonics can be found around critical frequencies of the receiver If the option exists the designer should choose a microprocessor that has the slowest rise and fall time po
33. ount2 f goto ttloop2 decfsz MS Tim f goto ttloop3 return Clear counter for this routine other counter being loaded Load working into MS Tim for any desired time period Load constant into working for Count2 Load working into Count2 register Countl1 becomes OxFF on first decrement Repeat until Countl equals zero Decrease secondary counter Repeat until Count2 equals zero Decrease MS Tim counter and skip when counter equals zero Repeat until MS Tim equals zero Return from delay routine 27 i lt SendBurst i lt Start movilw movwf call moviw movwf call moviw movwf call moviw movwf call moviw movwf call Send Entire Data Burst Routine b l1I1lI1111 TxByte Sendbyte b 00000000 TxByte Sendbyte OxF5 TxByte SendByte OxAA TxByte SendByte OxAA TxByte SendByte return call CheckPreamble CheckAdrO CheckAdr1 Chkbut movlw subwf btfss goto call movlw subwf btfss goto call movilw subwf btfss goto call call goto Main Loop GetByte OxF5 RxByte 0 status z Chkbut GetByte OxAA RxByte 0 status z Chkbut GetByte OxAA RxByte w status z Chkbut beep checkbutton Start Load Load Send Load Load Send Load Load Send Load Load Send Load Load Send Done Call first preamble byte into working working into TXByte register first preamble byte second preamble
34. rated in a residential area or any area where radio devices might be subject to harmful electrical interference This Kit has not been certified for use by the FCC in accord with Part 15 ETSI I ETS 300 220 or I ETS 300 220 1 regulations or other known stan dards of operation governing radio emissions Helf Y IH Ionoeg JOATIIOY SJUTO ISIL DADDA vary preoqpeouq sqHINOW ngJedunf uomnoeg 1ojmusuei L IOO 1HOR AdQ2 OT AOISURA IM S3001YNORYT JE W3LSAS LN3Nd013A3 yoer euuojuy S des se AFEFE Jepmusuei 0000 x DivLLTTT 000 FE BS5Si ges o 9 2 2 A n mr es PER 3 z eld s Gacr Ji i sung ATIJUIUWONW T sprs dId NOW opis nsoddo n NOW jueunreduro Iop oH Aeg A6 SPUWL Aey Nod TETSU quoura OZIg 10sso201doJoHq 2 2 Getting Started Required Equipment QDS QwikRadio Development System Two QDS development boards Figure 1 Two antennas Two 9 volt batteries QDS user s manual QDS Windows software Two computers each with one available 9 pin serial communication port and Windows 95 or later installed Two serial cables male to female DB9 Note 1 For RS 232 Windows based Software Testing Only Setup 1 Select a location that lends itself to wireless testing i e line of sight with as few metal objects and RF pathway obstructions as practical 2 Ensure that jumper and dipswitch settings match that required for desired test Units are shipped with the radios interfaced t
35. ssible for the given application to avoid problematic harmonics relative to the receiver Swithing power supplies brush type motors and other radio unfriendly devices should be avoided around the receive circuitry Adequate bypass capacitors chokes series resistors and shielding can be helpful in managing such problems 17 6 Low power Radios and Regulatory Compliance 6 1 Electromagnetic Compliance All low power radio utilizing a frequency 9 Khz or about is subject to electromagnetic compliance and conformance Often these devices use less than 1 mW or 0 dBm of power operate shorter distances 1 to 1000 feet and are simple in design These devices are unlicensed meaning that they may be used without the end user having to apply for any other type of FCC authorization In that the frequencies these devices use are shared by millions one has to take occupied bandwidth inference into account when determining if the desired application is suitable for this regulatory area Normally part 15 or low power radios are used for short range low cost applications where human life or safety are not considerations Among some of these are remote controls for automotive and home alarms garage door openers and simple contact closers amoung others Data and telemetry is also another area where Part 15 devices are employed QDS is intended to support the design of these types of low power wireless applications Most low power wireless systems operate with few in
36. tely 1600k to 200k Once the filter bandwidth is selected this resistance is determined then the value of capacitor C TH is easily calculated once the slicing level time constant is determined Values vary somewhat with decoder type but typical slicing level time constants range 5ms to 50ms Optimization of the C TH value will be required to maximize range 5 4 AGC Function and the AGC Capacitor The signal path features automatic gain control AGC to increase input dynamic range An external capacitor C AGC must be applied to set the AGC attack and decay time constants With the addition of only a capacitor the ratio of decay to attack time constant is fixed at 10 1 i e the attack time con stant is 1 10th the decay time constant and this ratio cannot be changed by the user However the attack time constant is selectable by the user through the value of capacitor C AGC By adding resis tance from the C AGC pin to VDDBB or VSSBB in parallel with the C AGC capacitor the ratio of decay to attack time constant may be varied 5 5 Antenna Design Considerations Three types of antennas are normally associated with QwikRadio applications 1 quarter wave monopole 2 helical coil and 3 pcb loop Of these antenna types the quarter wave monopole is preferred giving the best range performance Typical SR and SH receivers employing quarter wave monopole antennas generally provide about 100 meters open field range The QwikRadio IC
37. terference problems However these systems operate on shared radio channels so interference can occur at any place and at any time 6 2 A Regulatory Overview for The United States Although the QwikRadio series RFIC s normally do not exceed the FCC regulations for unintentional radiation the wireless developer should be aware of the requirements for the transmitter being used Non licensed transmitters operate on a variety of frequencies They must share these frequencies with licensed transmitters and are prohibited from causing interference to licensed transmitters The Federal Communications Commission FCC has rules to limit the potential for harmful interference to licensed transmitters by low power non licensed transmitters In its regulations the FCC takes into account that different types of products that incorporate low power transmitters have different potentials for causing harmful interference As a result the FCC s regulations are most restrictive on products that are most likely to cause harmful interference and less restrictive on those that are least likely to cause interference This overview is intended to provide a general understanding of the FCC s regulations and policies applying to products using low power transmitters It reflects the current text and interpretations of the FCC s regulations More detailed information is contained in the regulations themselves which can be found in Part 15 of Title 47 of the Code of Fe
38. tification is responsible for having the compli ance label produced and for having it affixed to each device that is marketed or imported The wording for the compliance label is in Part 15 and may be included on the same label as the FCC ID if desired The compliance label and FCC ID label may not be attached to any devices until a grant of certification has been obtained for the devices 20 Once the report demonstrating compliance with the technical standards has been completed and the compliance label and FCC ID label have been designed the party wishing to get the transmitter certified it can be anyone must file a copy of the report an Application for Equipment Authorization FCC Form 731 and an 845 application fee with the FCC After the application is submitted the FCC s lab will review the report and may or may not request a sample of the transmitter to test If the application is complete and accurate and any tests performed by the FCC s lab confirm that the transmitter is compliant the FCC will then issue a grant of certification for the transmitter Marketing of the transmitter may begin after the applicant has received a copy of this grant Typically 9096 of the applications for certification that the FCC receives are processed within 30 calen dar days This time frame may increase due to incomplete applications and pre grant sampling if deter mined to be necessary The verification procedure requires that tests b
39. tions are completely integrated The result is a highly reliable yet extremely low cost solution for high volume wireless applications Because the QwikRadio IC is a true single chip radio receiver it is extremely easy to apply minimizing design and production costs and improving time to market The QwikRadio IC provides two fundamental modes of operation FIXED and SWP In FIXED mode the device functions like a conventional superheterodyne receiver with an internal local oscillator fixed at a single frequency based on an external reference crystal or clock As withany conventional superheterodyne receiver the transmit frequency must be accurately controlled generally with a crystal or SAW Surface Acoustic Wave resonator In SWP mode the QwikRadio IC sweeps the internal local oscillator at rates greater than the baseband data rate This effectively broadens the RF band width of the receiver to a value equivalent to conventional super regenerative receivers Thus the QwikRadio C can operate with less expensive LC transmitters without additional components or tuning even though the receiver topology is still superheterodyne In this mode the reference crystal can be replaced with a less expensive 0 5 ceramic resonator All post detection demodulator data filtering is provided on the QwikRadio IC so no external filters need to be designed Any one of four filter bandwidths may be selected externally by the user Band
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