; Mark Crosbie 9/12/98 mark@mastincrosbie.com ; Scope test program. Flash an LED at a high frequency ; to observe changes. ; ; The Program simply sets up Bit 0 of Port "A" to Output and then ; loops, setting the value alternatively low and high ; ; Hardware Notes: ; Reset is tied through a 4.7K Resistor to Vcc and PWRT is Enabled ; A 220 Ohm Resistor and LED is attached to PORTA.0 and Vcc ; ; device pic16c84 include "p16c84.h" __CONFIG _CP_OFF & _WDT_OFF & _XT_OSC & _PWRTE_ON ; Mainline of FlashFast org 0 clrf PORTA ; Clear all the Bits in Port "a" clrf STATUS bsf STATUS, RP0 ; Goto Bank 1 to set Port Direction bcf TRISA, 0 ; Set RA0 to Output bcf STATUS, RP0 ; Go back to Bank 0 Loop movlw 1 ; Turn on the LED on Port A movwf PORTA ; movlw 5 call mdelay ; 5 uS delay movlw 0 ; Turn off the LED on Port A movwf PORTA ; movlw 5 call mdelay ; 5uS delay

goto Loop ; counter variables CNT dt 0 CNT1 dt 0 CNT2 dt 0 CNT3 dt 0 CNT4 dt 0 ; delay for w uS. Set the w register to the desired delay value MDELAY: MOVWF CNT ;LOAD DELAY TIME COUNT: NOP ;TWO NO OPERATIONS NOP ;TO OBTAIN THE DELAY DECFSZ CNT,1 ;DECREMENT THE COUNTER GOTO COUNT ;GOTO COUNT IF NOT FINNISHED RETURN end

;markrgen.asm - a program to generate 100, 50, 25, 10 and 5 Khz markers ; ; 10/23/99 Chuck Olson, WB9KZY ; ; WHATDUZITDO? ; ; This program uses a 16F84 PIC microcontroller to generate accurate ;square waves at frequencies of 100, 50, 25, 10 and 5 KHz. When the output ;is coupled via a very small value cap to a receiver, the odd and even ;harmonics of these markers can be heard all the way through to 30 MHz. ; The markers are selected via a momentary push button switch closure to ;ground on pin 1. At powerup, the PIC will output a 100 KHz signal ;to pin 6. If the momentary switch is pressed and released (PAR), the ;the output will change to 50 KHz - subsequent PARs will advance down ;to the 5 KHz marker and then wraparound back to the 100 KHz marker. ; ;If pin 2 is grounded, the marker will be gated (turned on and off at ;a regular interval). The frequency of the gating will increase as ;the user changes the markers to allow easy identification of the marker. ;The 100 KHz marker has a slow on/off tone while the 5 KHz marker will ;have a very rapid buzz. ; ;If pin 18 is grounded, the duty cycle will change from the normal 50% ;square wave to a 10% square wave. The idea was to even out the even ;and odd harmonic amplitudes, however, this isn't really accomplished ;but decided to leave it in anyway. It may (depending on the frequency) ;increase the amplitude of the even harmonics slightly. ; ;Programming notes: ; ; The program is basically a timed loop. The 100 KHz loop is the ;tightest, executing in 10 microseconds (us). With a 4 MHz clock the ;PIC executes all instructions in either 1 or 2 us. This makes it quite ;easy to simply count the cycles of the loop to allow for exactly the ;correct time delay - the PIC output is then set to a 1 or 0 as needed. ;Seperate loops are used for all 5 markers and duty cycles - there are ;undoubtedly more efficient ways to do this, but this method does work. ; ;The gating of the markers is accomplished with the use of the watch dog ;timer (WDT) feature of the PIC. The WDT is a seperate RC on-chip ;oscillator with a period of about 18 ms. The prescaler is used to count ;an integer number of WDT periods - after the prescaler overflows, the ;chip is reset, then a matching period of silence is generated using a ;timed loop. The loop to be executed is determined from the bits of ;the FSR register - the FSR register was used because it is left alone ;during a reset of the chip. ; ; Hardware notes: ; ; I built a prototype on perf board - I had a little trouble with ;adjusting the 4 MHz oscillator to be right on frequency - the value of ;the caps or something else may need to be changed - one of the ;two 33 pf caps connected to the crystal should be variable trimmer ;cap to allow this adjustment. It should be possible to use an external ;4 MHz oscillator to drive pin 16 instead of using a crystal although ;I haven't actually tried this. ; ; PIC pinout: ; ;pin name function/connection ;--- ---- ----------------------------------------------- ; 1 ra2 marker select, pulled up to +5V with a 10K resistor ; 2 ra3 gate select, pulled up to +5V with a 10 k resistor ; 3 ra4 no connect ; 4 MCLR pulled up to +5V with a 10K resistor ; 5 VSS Ground ; 6 rb0 marker output ; 7 rb1 no connect ; 8 rb2 no connect ; 9 rb3 no connect ; 10 rb4 no connect ; 11 rb5 no connect ; 12 rb6 no connect ; 13 rb7 no connect ; 14 VDD +5V ; 15 osc2 connected to one side of 4 MHz xtal, also 33 pf cap to gnd ; 16 osc1 connected to other side of 4 MHz crystal & 33 pf cap to gnd ; 17 ra0 no connect ; 18 ra1 duty cycle select, pulled up to +5V with a 10 k resistor LIST P=16F84, R=DEC INCLUDE "p16F84.inc" __FUSES _PWRTE_OFF & _CP_OFF & _WDT_ON & _XT_OSC ;constants ; bit definitions freq equ d'173' ;1/2 ms delay loop constant ; bit usage in the register FSR - bit 0 = 1 -> 100 KHz ; bit 1 = 1 -> 50 KHz ; bit 2 = 1 -> 25 KHz ; bit 3 = 1 -> 10 KHz ; bit 4 = 1 -> 5 KHz ; memory locations count equ 0x0C ;a delay loop counter variable temp equ 0x0D ;used in the delay loops temp2 equ 0x0E ;used in the delay loops temp3 equ 0x0F ;used in the delay loops ORG 0x000 prestart goto init ;reset vector ORG 0x004 noint goto init ;interrupt vector (shouldn't be needed) ; halfms - a routine to wait roughly 1/2 millisecond halfms movlw freq ;load up the delay constant movwf temp ;store it in the temporary location loopy decfsz temp,1 ;decrement the temp location - is it 0 ? goto loopy ;no, keep decrementing ;yes, return to the calling routine clrwdt ;clear the watchdog timer retlw 0 ;end of half cycle routine ; deboun - a routine to wait roughly 20 ms with paddle checking deboun movlw d'40' ;load up a counter for 20 ms (40 x .5 ms) db2 movwf temp2 ;store it in the second temp location loopdb decfsz temp2,1 ;decrement the dit length counter - is it 0 ? goto ckdel ;no, start checking and waiting goto dbdun ;yes, you're done ckdel ;call padchk ;get the paddle status (13 us) call halfms ;wait a .5 ms goto loopdb ;continue dbdun retlw 0 ;end of the debounce routine ; init - the initialization power up entry point of the program init bsf STATUS,5 ;set the bank bit to 1 movlw b'00000000' ; all outputs on PORTB movwf TRISB ; set the tri-state register movlw b'00001110' ; RA1,2,3 are inputs movwf TRISA ; set the tri-state register movlw b'00001101' ; set WDT for 32x (101) prescale movwf OPTION_REG ; set the option register bcf STATUS,5 ;set the bank bit to 0 waithlf btfsc FSR,0 ;test for 100 khz movlw d'16' ;load up a .32 second delay (.02 x 16) btfsc FSR,1 ;test for 50 khz movlw d'8' ;load up a .16 second delay (.02 x 8) btfsc FSR,2 ;test for 25 khz movlw d'4' ;load up a .08 second delay (.02 x 4) btfsc FSR,3 ;test for 10 khz movlw d'2' ;load up a .04 second delay (.02 x 2) btfsc FSR,4 ;test for 5 khz movlw d'1' ;load up a .02 second delay (.02 x 1) movwf temp3 ;store it in the temporary location loopx call deboun ;wait 20 ms to debounce the switch decfsz temp3,1 ;decrement the temp location - is it 0 ? goto loopx ;no, keep decrementing ;yes, see which loop we are in btfsc FSR,0 ;test for 100 khz goto strt1001 ;start with 100 KHz btfsc FSR,1 ;test for 50 khz goto strt501 ;start with 50 KHz btfsc FSR,2 ;test for 25 khz goto strt251 ;start with 25 KHz btfsc FSR,3 ;test for 10 khz goto strt101 ;start with 10 KHz btfsc FSR,4 ;test for 5 khz goto start51 ;start with 5 KHz ; rotate - a routine to select the next marker frequency rotate ;first, debounce the switch (wait for 40 ms) clrwdt ;clear the watchdog timer call deboun ;wait 20 ms to debounce the switch call deboun ;wait another 20 ms to debounce the switch btfss PORTA,2 ;has the switch been released? goto rotate ;no, wait another delay time ;yes, drift into the 100 Khz loop ; 100 khz loop ; PORTB bit 0, 5 usec high, 5 usec low strt1001 bsf STATUS,5 ;set the bank bit to 1 movlw b'00001101' ; set WDT for 32x (101) prescale movwf OPTION_REG ; set the option register bcf STATUS,5 ;set the bank bit to 0 movlw 0x01 ;load up the flag for 100 khz movwf FSR ;store it in loop strt100 bsf PORTB,0 ;1 1 set output (pin 6) high btfss PORTA,3 ;2 3 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfss PORTA,1 ;2 5 has the button on pin 18 been pressed? goto estr100 ; it's pressed, enter the 10% duty cycle loop bcf PORTB,0 ;1 6 set output (pin 6) low btfss PORTA,2 ;2 8 has the button on pin 1 been pressed? goto rotat50 ;yes, bail to the rotate to a new loop routine goto strt100 ;2 10 keep at it ; 10 % duty cycle 100 khz loop estr100 bsf PORTB,0 ;1 1 set output (pin 6) high bcf PORTB,0 ;1 2 set output (pin 6) low btfss PORTA,3 ;2 4 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfsc PORTA,1 ;2 6 has the button on pin 18 been released? goto strt100 ; it's released, enter the 50% duty cycle loop btfss PORTA,2 ;2 8 has the button on pin 1 been pressed? goto rotat50 ;yes, bail to the rotate to a new loop routine goto estr100 ;2 10 keep at it ; rotat50 - a routine to select the next marker frequency rotat50 ;first, debounce the switch (wait for 40 ms) clrwdt ;clear the watchdog timer call deboun ;wait 20 ms to debounce the switch call deboun ;wait another 20 ms to debounce the switch btfss PORTA,2 ;has the switch been released? goto rotat50 ;no, wait another delay time ;yes, drift into the 50 Khz loop ; 50 khz loop ; PORTB bit 0, 10 usec high, 10 usec low strt501 bsf STATUS,5 ;set the bank bit to 1 movlw b'00001100' ; set WDT for 16x (100) prescale movwf OPTION_REG ; set the option register bcf STATUS,5 ;set the bank bit to 0 movlw 0x02 ;load up the flag for 50 khz movwf FSR ;store it in loop start50 bsf PORTB,0 ;1 1 set output (pin 6) high btfss PORTA,3 ;2 3 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfss PORTA,1 ;2 5 has the button on pin 18 been pressed? goto estr50 ; it's pressed, enter the 10% duty cycle loop f50k2 goto f50k3 ;2 7 waste 2 cycles f50k3 goto f50k4 ;2 9 waste 2 cycles f50k4 nop ;1 10 waste 1 cycle bcf PORTB,0 ;1 11 set output (pin 6) low goto f50k5 ;2 13 waste 2 cycles f50k5 goto f50k6 ;2 15 waste 2 cycles f50k6 btfss PORTA,2 ;2 17 has the button on pin 1 been pressed? goto rotat25 ;yes, bail to the rotate to a new loop routine f50k7 nop ;1 18 waste 1 cycle goto start50 ;2 20 keep at it ; 10 % loop for 50 KHz estr50 bsf PORTB,0 ;1 1 set output (pin 6) high nop ;1 2 waste 1 cycle bcf PORTB,0 ;1 3 set output (pin 6) low btfss PORTA,3 ;2 5 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfsc PORTA,1 ;2 7 has the button on pin 18 been released? goto start50 ; it's released, enter the 50% duty cycle loop ef50k2 goto ef50k3 ;2 9 waste 2 cycles ef50k3 goto ef50k4 ;2 11 waste 2 cycles ef50k4 goto ef50k5 ;2 13 waste 2 cycles ef50k5 goto ef50k6 ;2 15 waste 2 cycles ef50k6 btfss PORTA,2 ;2 17 has the button on pin 1 been pressed? goto rotat25 ;yes, bail to the rotate to a new loop routine ef50k7 nop ;1 18 waste 1 cycle goto estr50 ;2 20 keep at it ; rotat25 - a routine to select the next marker frequency rotat25 ;first, debounce the switch (wait for 40 ms) clrwdt ;clear the watchdog timer call deboun ;wait 20 ms to debounce the switch call deboun ;wait another 20 ms to debounce the switch btfss PORTA,2 ;has the switch been released? goto rotat25 ;no, wait another delay time ;yes, drift into the 25 Khz loop ; 25 khz loop ; PORTB bit 0, 20 usec high, 20 usec low strt251 bsf STATUS,5 ;set the bank bit to 1 movlw b'00001011' ; set WDT for 8x (011) prescale movwf OPTION_REG ; set the option register bcf STATUS,5 ;set the bank bit to 0 movlw 0x04 ;load up the flag for 25 khz movwf FSR ;store it in loop start25 bsf PORTB,0 ;1 1 set output (pin 6) high btfss PORTA,3 ;2 3 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfss PORTA,1 ;2 5 has the button on pin 18 been pressed? goto estr25 ; it's pressed, enter the 10% duty cycle loop f50k9 goto f50ka ;2 7 waste 2 cycles f50ka goto f50kb ;2 9 waste 2 cycles f50kb goto f50kc ;2 11 waste 2 cycles f50kc goto f50kd ;2 13 waste 2 cycles f50kd goto f50ke ;2 15 waste 2 cycles f50ke goto f50kf ;2 17 waste 2 cycles f50kf goto f50kg ;2 19 waste 2 cycles f50kg nop ;1 20 waste 1 cycle bcf PORTB,0 ;1 21 set output (pin 6) low goto f50kh ;2 23 waste 2 cycles f50kh goto f50ki ;2 25 waste 2 cycles f50ki goto f50kj ;2 27 waste 2 cycles f50kj goto f50kk ;2 29 waste 2 cycles f50kk goto f50kl ;2 31 waste 2 cycles f50kl goto f50km ;2 33 waste 2 cycles f50km goto f50kn ;2 35 waste 2 cycles f50kn btfss PORTA,2 ;2 37 has the button on pin 1 been pressed? goto rotat10 ;yes, bail to the rotate to a new loop routine f50ko nop ;1 38 waste 1 cycle goto start25 ;2 40 keep at it ; 10 % duty cycle loop, 25 KHz estr25 bsf PORTB,0 ;1 1 set output (pin 6) high nop ;1 2 waste 1 cycle ef50k9 goto ef50ka ;2 4 waste 2 cycles ef50ka bcf PORTB,0 ;1 5 set output (pin 6) low btfss PORTA,3 ;2 7 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfsc PORTA,1 ;2 9 has the button on pin 18 been released? goto start25 ; it's released, enter the 50% duty cycle loop ;total loop count of high loop is 7 x 3 + 2 = 23 movlw 8 ;1 10 movwf count ;1 11 efloop1 decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto efloop1 ;2 34 loop back nop ;1 35 waste a cycle ef50kn btfss PORTA,2 ;2 37 has the button on pin 1 been pressed? goto rotat10 ;yes, bail to the rotate to a new loop routine ef50ko nop ;1 38 waste 1 cycle goto estr25 ;2 40 keep at it ; rotat10 - a routine to select the next marker frequency rotat10 ;first, debounce the switch (wait for 40 ms) clrwdt ;clear the watchdog timer call deboun ;wait 20 ms to debounce the switch call deboun ;wait another 20 ms to debounce the switch btfss PORTA,2 ;has the switch been released? goto rotat10 ;no, wait another delay time ;yes, drift into the 10 Khz loop ; 10 khz loop ; PORTB bit 0, 50 usec high, 50 usec low strt101 bsf STATUS,5 ;set the bank bit to 1 movlw b'00001010' ; set WDT for 4x (010) prescale movwf OPTION_REG ; set the option register bcf STATUS,5 ;set the bank bit to 0 movlw 0x08 ;load up the flag for 10 khz movwf FSR ;store it in loop start10 bsf PORTB,0 ;1 1 set output (pin 6) high movlw d'14' ;1 2 load up a loop countmovwf count ;1 3 save it movwf count ;1 3 save the count btfss PORTA,3 ;2 5 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfss PORTA,1 ;2 7 has the button on pin 18 been pressed? goto estrt10 ; it's pressed, enter the 10% duty cycle loop goto ohigh ;2 9 waste 2 cycles ;total loop count of high loop is 13 x 3 + 2 = 41 ohigh decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto ohigh ;2 50 loop back bcf PORTB,0 ;1 51 set output (pin 6) low movlw d'14' ;1 52 load up a loop count movwf count ;1 53 save it ;total loop count of high loop is 13 x 3 + 2 = 41 olow decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto olow ;2 94 loop back goto herep1 ;2 96 waste 2 cycles herep1 btfss PORTA,2 ;2 98 has the button on pin 1 been pressed? goto rotate5 ;yes, bail to the rotate to a new loop routine goto start10 ;2 100 keep at it ; 10 % duty cycle loop for 10 KHz estrt10 bsf PORTB,0 ;1 1 set output (pin 6) high movlw 15 ;1 2 load up a loop count movwf count ;1 3 save it btfss PORTA,3 ;2 5 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfsc PORTA,1 ;2 7 has the button on pin 18 been released? goto start10 ; it's released, enter the 50% duty cycle loop nop ;1 8 waste a cycle goto eohigh ;2 10 eohigh bcf PORTB,0 ;1 11 set output (pin 6) low movlw 28 ;1 12 load up a loop count movwf count ;1 13 save it ;total loop count of high loop is 27 x 3 + 2 = 83 eolow decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto eolow ;2 96 loop back eherep1 btfss PORTA,2 ;2 98 has the button on pin 1 been pressed? goto rotate5 ;yes, bail to the rotate to a new loop routine goto estrt10 ;2 100 keep at it ; rotate5 - a routine to select the next marker frequency rotate5 ;first, debounce the switch (wait for 40 ms) clrwdt ;clear the watchdog timer call deboun ;wait 20 ms to debounce the switch call deboun ;wait another 20 ms to debounce the switch btfss PORTA,2 ;has the switch been released? goto rotate5 ;no, wait another delay time ;yes, drift into the 5 Khz loop ; 5 khz loop ; PORTB bit 0, 100 usec high, 100 usec low start51 bsf STATUS,5 ;set the bank bit to 1 movlw b'00001001' ; set WDT for 2x (001) prescale movwf OPTION_REG ; set the option register bcf STATUS,5 ;set the bank bit to 0 movlw 0x10 ;load up the flag for 5 khz movwf FSR ;store it in loop start5 bsf PORTB,0 ;1 1 set output (pin 6) high movlw 31 ;1 2 load up a loop count movwf count ;1 3 save it btfss PORTA,3 ;2 5 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfss PORTA,1 ;2 7 has the button on pin 18 been pressed? goto estrt5 ; it's pressed, enter the 10% duty cycle loop ;total loop count of high loop is 30 x 3 + 2 = 92 ohigh2 decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto ohigh2 ;2 99 loop back nop ;1 100 waste a cycle outlow bcf PORTB,0 ;1 101 set output (pin 6) low movlw 31 ;1 102 load up a loop count movwf count ;1 103 save it ;total loop count of high loop is 31 x 3 + 2 = 92 olow2 decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto olow2 ;2 195 loop back nop ;1 196 waste a cycle btfss PORTA,2 ;2 198 has the button on pin 1 been pressed? goto rotate ;yes, bail to the rotate to a new loop routine goto start5 ;2 200 keep at it ; 10 % duty cycle loop for 5 KHz estrt5 bsf PORTB,0 ;1 1 set output (pin 6) high movlw 4 ;1 2 load up a loop count movwf count ;1 3 save it btfss PORTA,3 ;2 5 has the button on pin 2 been pressed? clrwdt ; it's pressed, clear the wdt (no gate) btfsc PORTA,1 ;2 7 has the button on pin 18 been released? goto start5 ; it's released, enter the 50% duty cycle loop ;total loop count of high loop is 3 x 3 + 2 = 11 eohigh2 decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto eohigh2 ;2 18 loop back goto eoutlow ;2 20 waste 2 cycles eoutlow bcf PORTB,0 ;1 21 set output (pin 6) low movlw 58 ;1 22 load up a loop count movwf count ;1 23 save it ;total loop count of high loop is 57 x 3 + 2 = 173 eolow2 decfsz count,1 ;1 (2) decrement the loop count - skip at 0 goto eolow2 ;2 196 loop back btfss PORTA,2 ;2 198 has the button on pin 1 been pressed? goto rotate ;yes, bail to the rotate to a new loop routine goto estrt5 ;2 200 keep at it END

Pin	Name	Function / Connection
1	ra2	marker select, pulled up to +5V with a 10K resistor
2	ra3	gate select, pulled up to +5V with a 10 k resistor
3	ra4	no connect
4	MCLR	pulled up to +5V with a 10K resistor
5	Vss	Ground
6	rb0	marker output
7	rb1	no connect
8	rb2	no connect
9	rb3	no connect
10	rb4	no connect
11	rb5	no connect
12	rb6	no connect
13	rb7	no connect
14	Vdd	+5V
15	osc2	connected to one side of 4 MHz xtal, also 33 pf cap to gnd
16	osc1	connected to other side of 4 MHz crystal & 33 pf cap to gnd
17	ra0	no connect
18	ra1	duty cycle select, pulled up to +5V with a 10 k resistor