AN1833 Freescale Semiconductor / Motorola, AN1833 Datasheet
AN1833
Related parts for AN1833
AN1833 Summary of contents
Page 1
... SAW resonator oscillator typically shifts 150 kHz. A standard OOK receiver is designed with a wideband response to capture the drifted transmitter at the expense of sensitivity and selectivity. © Motorola, Inc., 2000 For More Information On This Product, AN1833 Go to: www.freescale.com Order this document by AN1833/D AN1833 ...
Page 2
... The field strength of emissions from intentional radiators from 260 to 470 MHz is limited to 12,500 microvolts per meter measured at three 2 For More Information On This Product, Go to: www.freescale.com AN1833 MOTOROLA ...
Page 3
... FM (frequency modulation) detector, etc.). A reliable TRF receiver at UHF (ultra-high frequency) frequencies is difficult to achieve because appreciable AN1833 MOTOROLA For More Information On This Product, Tuned radio frequency (TRF) Superheterodyne receivers Go to: www ...
Page 4
... MC13176D [4] which operates under an inexpensive crystal reference source from a microcontroller unit, the MC68HC705J1A [5]. Baseband processing functions are performed by MCUs in both the remote receiver and handheld transmitter. 4 Figure 1a (Figure 1b) is implemented by using a versatile For More Information On This Product, Go to: www.freescale.com has many advantages over a AN1833 MOTOROLA ...
Page 5
... Freescale Semiconductor, Inc. ANTENNA LNA MC13144 OR MRFIC0916 SWITCHING OUTPUT Figure 1a. OOK Receiver Block Diagram AN1833 MOTOROLA For More Information On This Product, V MC13158FTB CC SINGLE-CONVERSION RECEIVER TTL DATA OUT MC68HC705J1A to: www.freescale.com Application Note Application Overview 4-MHz ...
Page 6
... CC f/ ENABLE REFERENCE INPUT 12 MHz MC68HC705J1A For More Information On This Product, Go to: www.freescale.com RF OUT 4-MHz FUND XTAL MC34164 V SS MOTOROLA AN1833 ...
Page 7
... The oscillator transistor internally drives the mixer and can be operated oscillator to greater than 450 MHz. The application circuit (see controlled oscillator (VCO) to provide LO drive at approximately 395 MHz. AN1833 MOTOROLA For More Information On This Product, Differential input mixer 40-dB IF amplifier ...
Page 8
... For positive logic data output, the data signal goes to the EE non-inverting input. Where the reference input pin of the data slicer is 8 about the dc level to the comparator input. BE For More Information On This Product, Go to: www.freescale.com to ground to match the 10.7-MHz . EE AN1833 MOTOROLA ...
Page 9
... The RSSI output is fed to the data slicer, which shapes the recovered RSSI data into a rail-to-rail logic swing. In the following sections, each part of the OOK receiver is explained in more detail. AN1833 MOTOROLA For More Information On This Product, Receiver Application Circuit Description/Design 1a. The complete schematic of the MC13144 and MC13158 Go to: www ...
Page 10
... For More Information On This Product, Go to: www.freescale.com 4.7 pF 4.7 pF MMBV809L 1 F ENABLE RSSI OUT 25 ENABLE 24 23 100 OUT 19 DS OFF – EE2 470 820 TBD TBD MOTOROLA + AN1833 ...
Page 11
... This equation shows the relationship (0.159 [(C1)(C2)] / [( [L] }1/2] where C is the equivalent capacitance of CB, CS, and CV. The relationship for )(CB CV) AN1833 MOTOROLA For More Information On This Product, External Varactor Controlled Local Oscillator is a schematic of the receiver external local oscillator circuit. ...
Page 12
... L is calculated to be 11.5 nH. For a more in-depth study, Randall Rhea discusses several oscillator circuits in his book on oscillator design [7 (CS + CV)(CB [(C1)(C2)] / [( )(CB [(C1)(C2)] / [( (CS + CV)(CB (at 2.2 Vdc For More Information On This Product, Go to: www.freescale.com } 1/ AN1833 MOTOROLA ...
Page 13
... Freescale Semiconductor, Inc #28AWG enameled wire wound on a #74 drill bit. The VCO is fine tuned AN1833 MOTOROLA For More Information On This Product, External Varactor Controlled Local Oscillator 3 ENABLE NC EE1 MC13158FTB by adjusting the spacing between windings of this air core inductor ...
Page 14
... LO is above the RF). The ground reference of the varactor is taken 14 V17 = { [ (R15/R17 (R15/R17 diode drop = 0.75 Vdc bias to the discriminator output An offset to dc match the loop filter frequency versus voltage out response to VCO control characteristic For More Information On This Product, Go to: www.freescale.com versus Out BE AN1833 MOTOROLA ...
Page 15
... The filter bandwidth is affected by its source impedance and output load impedances which are 330 . The MC13158 mixer output and IF amplifier input and output impedances are 330 10.7-MHz ceramic filters. AN1833 MOTOROLA For More Information On This Product, (ac ground); thus, the LO frequency increases as the varactor (10 ...
Page 16
... The choice of this EE / directly proportionate to this load. Out In Figure . These components form a low pass filter with its EE will suffice). Should the receiver system be CC For More Information On This Product, Go to: www.freescale.com 5). The RSSI output rise and fall with a EE AN1833 MOTOROLA ...
Page 17
... The secondary output of the transformer uses a tapped capacitor transformer to provide a lower source impedance to the reference input of the MC13176 (pin 9) while forming a second LC resonant network. Thus, the tripler circuit is a double tuned LC network which provides increased selectivity of the 12-MHz signal. AN1833 MOTOROLA For More Information On This Product, 35.0 30.0 25 ...
Page 18
... V ground side where leaded components are mounted and only a few necessary circuit traces are done. portions of the circuit. side of the PCB. where the pins of the IC contact the trace on the PC EE board. For More Information On This Product, Go to: www.freescale.com EE AN1833 MOTOROLA ...
Page 19
... IF bandwidth. The application circuit supports data rates kHz. This has been confirmed in the lab with relaxed interstage and baseband filtering. The wider filtering is much more susceptible to interference. AN1833 MOTOROLA For More Information On This Product, Figure 8 shows a plot of the hold-in range and pull-in range Go to: www ...
Page 20
... Figure 6. 384-MHz OOK Transmitter For More Information On This Product, Go to: www.freescale.com 300 Vdc CC 4-MHz FUND XTAL MC68HC705J1A MC34164P MOTOROLA AN1833 ...
Page 21
... Freescale Semiconductor, Inc. 395.5 395.0 394.5 394.0 AN1833 MOTOROLA For More Information On This Product, 0 – 20 – 40 – 60 – 80 – 100 – 120 – 140 1 10 100 1 k FREQUENCY, f (Hz) Figure 7. Phase Noise versus Frequency See Figure 2 – 90 – 80 – 70 – INUPUT LEVEL (dBm) Figure 8 ...
Page 22
... MC13176 turns on when a keypad button is depressed. Decoding of which key is depressed is done using the routines written by David Yoder [12]. The ISR examines the port A input values when certain port B outputs are asserted. 22 unit turning on a light For More Information On This Product, Go to: www.freescale.com AN1833 MOTOROLA ...
Page 23
... MCU will perform actions specified in the command byte. AN1833 MOTOROLA For More Information On This Product, Microcontroller Software Overview: Initiate an Access Request 10 ...
Page 24
... STORE KEYPAD INPUT RELEASE OF THE KEY IN ADDRESS BYTE SET FIRST FLAG BIT RETURN FROM INTERRUPT For More Information On This Product, Go to: www.freescale.com KeyPad_Body is a subroutine that decodes keypad. Refer to AN1239/D. STORE KEYPAD INPUT YES IN COMMAND BYTE NO Send_preamble SEE SHEET 2 MOTOROLA AN1833 ...
Page 25
... YES LENGTH = COMMAND CONTAINS THE SECOND DECODED KEYPAD VALUE. SEE SHEET 1 Figure 10. Transmitter MCU Flowchart (Sheet AN1833 MOTOROLA For More Information On This Product, Microcontroller Software Overview: Initiate an Access Request WAIT 5 ms CREATES A LOGIC 1 “FRONT PORCH” OF 500 s WAIT 500 s ...
Page 26
... AND FLAGS GET FOUR BITS OF DATA AND LOOK FOR ALL FOUR BITS EQUAL TO LOGIC 1. Get_Bit Front_Porch DECREMENT BIT COUNT YES BIT COUNT = For More Information On This Product, Go to: www.freescale.com Get_Bit IS SHOWN IN AN1240/D. YES RECEIVED BITS = 1 Get_Data ? NO SEE SHEET 2 MOTOROLA AN1833 ...
Page 27
... ALLOW INTERRUPTS BUFFER INDEX = 0 main_loop BUFFER (INDEX) = BYTE RECEIVED INDEX COUNT = 4 ? INCREMENT INDEX COUNT Figure 12. Receiver MCU Flowchart (Sheet AN1833 MOTOROLA For More Information On This Product, Microcontroller Software Overview: Initiate an Access Request BUFFER INDEX = LENGTH get_char YES WAIT FOR TIMER INTERRUPT check_msg_format ON SHEET 3 WHEN THE TIMER INTERRUPT OCCURS ...
Page 28
... YES BUFFER (INDEX) = B’CAST YES TURN ON I/O PIN = FA? NO YES TURN OFF I/O PIN = FB? NO For More Information On This Product, Go to: www.freescale.com prev55 NO NOT THIS UNIT’S ADDRESS NO main SEE SHEET 1 DEFECTIVE COMMAND BYTE MOTOROLA AN1833 ...
Page 29
... FCC regulations. It also fits manufacturing cost goals. Both RF components interface well with the MC68HC705J1A MCU to provide more robust and dependable data recovery which ensures error- free switching of remote devices. AN1833 MOTOROLA For More Information On This Product, Go to: www.freescale.com Application Note ...
Page 30
... MC68HC705J1A; document order number AN1239/D, Motorola, Inc. [13] George, Scott. HC05 Software-Driven Asynchronous Serial Communication Techniques Using the MC68HC705J1A; document order number AN1240/D; Motorola, Inc. [14] Sibigtroth, James M. Understanding Small Microcontrollers, document order number M68HC05TB/D; Motorola, Inc. 30 For More Information On This Product, Go to: www.freescale.com AN1833 MOTOROLA ...
Page 31
... PORTA sta DDRA AN1833 MOTOROLA For More Information On This Product, ; port used for serial port pins ; port used for driving LED's. ; pin # for noise LED ; pin # for frame LED ; pin # for receive data pin ; pin # for transmit data pin ...
Page 32
... For More Information On This Product, Go to: www.freescale.com * * * * AN1833 MOTOROLA ...
Page 33
... AN1833 MOTOROLA For More Information On This Product, ; get the key-pad character ; send out key-pad character ; insert a 12 cycle timing stall so ; receiver and transmitter routines take ; the same time between sent characters ; send address byte ...
Page 34
... Any decoding of external interrupts ; should be done here. ; The external and keypad interrupt share ; this vector. ;See if a key is pressed ;If no key down, return to save power For More Information On This Product, Go to: www.freescale.com * * 6 2--\ 3-\| 2 || 3-/| 3--/ * * * * * * * * AN1833 MOTOROLA ...
Page 35
... KeyPad_Table,x beq KeyPad030 decx AN1833 MOTOROLA For More Information On This Product, ;Debounce key for 4mS ;Jump to delay routine ;Get the keypress ;If no key down, return ;no key down = 00 in acu ; branch if first key seen ; store address code ...
Page 36
... IRQs ; SOSCD = Short Oscillator delay ; enable For More Information On This Product, Go to: www.freescale.com Column PB0 PB1 PB2 PB3 PB0 PB1 PB2 PB3 PB0 PB1 PB2 PB3 PB0 PB1 PB2 PB3 AN1833 MOTOROLA ...
Page 37
... Program Constant Equates: AN1833 MOTOROLA For More Information On This Product, ; EPMSEC = EPROM Security ; OSCRES = Ocscillator Parallel ; Resistor ; SWAIT = Stop Instruction Mode ; SWPDI = Port Pulldown Inhibit ; PIRQ = Port A Interrupt Function ; LEVEL = IRQ Edge Sensitivity ; COPEN = COP Watchdog enable ...
Page 38
... For More Information On This Product, Go to: www.freescale.com 4MHz osc 2MHz osc 9600 4800 2400 1200 600 600 300 - bit 0 = got MOTOROLA * AN1833 ...
Page 39
... AN1833 MOTOROLA For More Information On This Product, timer interval is 8.2 msec ; initialize timer register ; and allow interrupts ; clear I bit in CCR ; initialize the index ; store in memory ; receive one byte of data from rxd pin ; get the current character ...
Page 40
... ISCR external ; interrupts from IRQ Port A ; load TSCR (timer Control turn ; off RTIC= RTI enable, ; clear RTIFlag For More Information On This Product, Go to: www.freescale.com * * * * * * * - data from the receiver AN1833 MOTOROLA ...
Page 41
... AN1833 MOTOROLA For More Information On This Product RTI = enable, clear RTI Flag ; clear buffers ; clear 55 flag ; cleaar receiver memory location ; clear index counter ; clear receive buffer ; location 0 ; location 1 ; location 2 ...
Page 42
... For More Information On This Product, Go to: www.freescale.com * * * * * * * * * AN1833 MOTOROLA ...
Page 43
... RESET fdb main org Timer_INT fdb Timer_SVR AN1833 MOTOROLA For More Information On This Product, ;[2] this is a 13-cycle loop ;[2] ;[3] ;[3] decrement loop count ;[3] loop if count not zero ;[6] exit (delay_13a) ; When reset occurs routine main ; When interrupt occurs routine ...
Page 44
... JAPAN: Motorola Japan Ltd.; SPS, Technical Information Center, 3-20-1, Minami-Azabu, Minato-ku, Tokyo 106-8573 Japan. 81-3-3440-3569 ASIA/PACIFIC: Motorola Semiconductors H.K. Ltd.; Silicon Harbour Centre, 2 Dai King Street, Tai Po Industrial Estate, Tai Po, N.T., Hong Kong. 852-26668334 Technical Information Center: 1-800-521-6274 HOME PAGE: http://www.motorola.com/semiconductors/ For More Information On This Product, Go to: www.freescale.com © Motorola, Inc., 2000 AN1833/D ...