;U賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽U ;U CONTENTS : Simple low-cost 7-digit universal UHF/VHF frequency meter U ;U based on the PIC16F84 U ;U COPYRIGHT: Peter Halicky OM3CPH U ;U AUTHOR : Peter Halicky OM3CPH U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U E-Mail: halicky@minv.sk or om3cph@oe3xbs.aut.eu U ;U U ;U Bratislava, Slovakia, February, 2000 U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U This is 7-digit frequency meter measuring frequency from 10 Hz up to U ;U 1300 MHz. It is based on ideas of PIC16F84 based frequency meter. U ;U The measuring range is divided into two subranges: 10Hz - 20MHz and U ;U 20 MHz - 1300MHz. The decimal point is after MHz digit, but can be set U ;U at any position. U ;U U ;U Hardware is very simple: U ;U U ;U It contains : PIC 16F84 U ;U 74HC137 (BCD -> 1 of 8 decoder) U ;U SAB6456 VHF-UHF divider by 256 U ;U 7-digit calculator display (common cathode), U ;U some resistors, capacitors and 2 switching diodes U ;U Note: U ;U "Calculator display" means (say) 7 digit LED multiplexed display. U ;U Both common cathode and common anode can be used. Software is written U ;U for common cathode. For common anode displays it requires some softwa- U ;U re and hardware modification. U ;U U ;U PIC is used as 3 byte counter. If it counts 0.1 s maximum measured U ;U frequency is FF FF FF, e. g. 167.77215 MHz (theoretically). U ;U SAB6456 is used as 1:256 predivider. Its upper limit is 1300MHz. U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U U ;U The device uses internal prescaler of PIC as low byte of counter, U ;U TMR0 as middle byte and some register as high byte of counter. The U ;U software DOESN'T read anything from any input port. RA4 is used as U ;U prescaler input. U ;U U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U U ;U Measuring period is 100 000 us (HF) or 256 000 us (VHF and UHF). U ;U U ;U The main steps during measuring period: U ;U U ;U 1. start measurement, U ;U 2. precode decimal value of digit to segments, U ;U 3. if it's correct digit set decimal point, U ;U 4. output to PortB, U ;U 5. output digit number to PortA U ;U 6. test TMR0 overflow bite, if YES increase TimerH, U ;U 7. leave digit to light, U ;U 8. increase digit number, U ;U 9. if <7 goto 2, U ;U 10. else zero digit number, decrease counter and goto 2, U ;U 11. stop measurement, U ;U 12. test TMR0 overflow bite, if YES increase TimerH, U ;U 13. shift out precounter content, U ;U 14. check signal at RB0 and switch range accordingly, U ;U 15. recode 3-byte value into 7 decimal numbers, U ;U 16. goto 1 U ;U U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U U ;U Total timing formula: U ;U U ;U For low frequency N = Fx * 100 000/4 U ;U For VHF-UHF N = Fx * 256 000/4 respectively U ;U U ;U N = T*[7*(34+3*T1)+6+3*T2]+9+9*T3+Z U ;U U ;U where T,T1,T2,T3 are initial values of timing loops, U ;U Z are additional fine tunig NOPs, U ;U Fx Xtal frequency in MHz. U ;U U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U Some ideas were taken from "Simple low-cost digital frequency meter U ;U using a PIC 16C54" (frqmeter.asm) U ;U written by James Hutchby, MadLab Ltd. 1996 U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U U ;U This software is free for private usage. It was created for HAM radio U ;U community members. Commercial exploatation is allowed only with U ;U permission of authors. U ;U U ;U複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複U include ;컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 Index equ 0Ch ; dummy register Count equ 0Dh ; inkremental register Help equ 0Eh ; dummy register LED0 equ 0Fh LED1 equ 010h LED2 equ 011h LED3 equ 012h LED4 equ 013h LED5 equ 014h LED6 equ 015h UHF equ 016h ; semaphore register TimerH equ 017h ; higher byte of SW counter LowB equ 018h ; low byte of resulted frequency MidB equ 019h ; middle byte of resulted frequency HigB equ 01Ah ; high byte of resulted frequency Temp equ 01Bh ; temporary register HIndex equ 01Ch ; index register LEDIndex equ 01Dh ; LED pointer MTT equ 01Eh ; working timer registers TM1 equ 01Fh ; TM2 equ 020h ; TM3 equ 021h ; MD equ 022h ; dot position MT equ 023h ; timing loop registers T1 equ 024h ; 1st timer loop T2 equ 025h ; 2nd timer loop T3 equ 026h ; 3rd timer loop - values for 10 MHz Xtal D equ 027h ; decimal point position UT equ 028h ; the main timing loop U1 equ 029h ; 1st timer loop U2 equ 02Ah ; 2nd timer loop U3 equ 02Bh ; 3rd timer loop UD equ 02Ch ; decimal point position ;컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴 org 0 Start clrf Index clrf LEDIndex clrf LED0 clrf LED1 clrf LED2 clrf LED3 clrf LED4 clrf LED5 clrf LED6 clrf LowB clrf MidB clrf HigB movlw .94 ; low frequency timers movwf MT movlw .114 movwf T1 movlw .5 movwf T2 movlw .2 movwf T3 movlw 5 movwf D movlw .94 ; timers starting values movwf MTT movlw .114 movwf TM1 movlw .5 movwf TM2 movlw .2 movwf TM3 movlw 5 movwf MD movlw .160 ; VHF-UHF timers movwf UT movlw .178 movwf U1 movlw .4 movwf U2 movlw .1 movwf U3 movlw 3 movwf UD bsf STATUS,RP0 movlw b'00010000' ; RA0..RA3 outputs movwf TRISA ; RA4 input movlw b'00000000' ; RB0..RB7 outputs movwf TRISB clrwdt ; movlw b'00100111' ; Prescaler -> TMR0, movwf OPTION_REG ; 1:256, rising edge bcf STATUS,RP0 ; goto Entry ;�袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴敲 ;s The block of subroutines and constants tables s ;C袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴�L ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l 3 byte substraction of the constant from the table, it sets carry l ;l if result is negative l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 Subc24 clrf Temp ; it will temporary save CF movf Index,W ; pointer to low byte of constant movwf HIndex ; W -> HIndex call DecTable ; W returned with low byte of constant bsf STATUS,C ; set CF subwf LowB,F ; LowB - W -> LowB ; if underflow -> C=0 btfsc STATUS,C goto Step1 bsf STATUS,C movlw 1 subwf MidB,F ; decrement MidB ; if underflow -> C=0 btfsc STATUS,C goto Step1 bsf STATUS,C movlw 1 subwf HigB,F ; decrement HigB btfsc STATUS,C ; if underflow -> C=0 goto Step1 bsf Temp,C ; set C Step1 decf HIndex,F movf HIndex,W ; pointer to middle byte of const call DecTable bsf STATUS,C subwf MidB,F ; MidB - W -> MidB btfsc STATUS,C ; if underflow -> C=0 goto Step2 bsf STATUS,C movlw 1 subwf HigB,1 ; decrement HigB btfsc STATUS,C ; if underflow -> C=0 goto Step2 bsf Temp,C ; set C Step2 decf HIndex,F movf HIndex,W ; pointer to middle byte of constatnt call DecTable bsf STATUS,C subwf HigB,F ; HigB - W -> HigB btfsc STATUS,C ; if underflow -> C=0 goto ClearCF bsf STATUS,C goto SubEnd ClearCF rrf Temp,C ; C -> STATUS SubEnd retlw 0 ;========================================================================= ; 3 byte addition of the constant from the table, it sets carry if | ; result overflows | ;========================================================================= Addc24 clrf Temp ; register for temporary storage of CF movf Index,W ; pointer to lower byte of const into W movwf HIndex ; save it into HIndex call DecTable ; W contains low byte of const bcf STATUS,C ; clear C addwf LowB,1 ; W + LowB -> LowB btfss STATUS,C ; test overflow goto Add2 bcf STATUS,C ; clear C movlw 1 addwf MidB,F ; increment MidB btfss STATUS,C goto Add2 bcf STATUS,C movlw 1 addwf HigB,F ; increment HigB btfss STATUS,C ; test overflow goto Add2 bsf Temp,C ; store C Add2 decf HIndex,F ; pointer to middle byte into W movf HIndex,W call DecTable bcf STATUS,C addwf MidB,1 ; W + MidB -> MidB btfss STATUS,C goto Add3 bcf STATUS,C ; clear C movlw 1 addwf HigB,1 ; increment HigB btfss STATUS,C goto Add3 bsf Temp,C Add3 decf HIndex,F ; pointer to higher byte into W movf HIndex,W call DecTable bsf STATUS,C addwf HigB,F ; W + HigB -> HigB, btfss STATUS,C goto ClarCF bsf STATUS,C goto AddEnd ClarCF rrf Temp,C ; C -> STATUS AddEnd retlw 0 ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훭 ;l Tables of 3-byte constants l ;A컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� ;l Table of decades l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U DecTable addwf PCL,F ; W + PCL -> PCL retlw 0 ; 10 retlw 0 ; retlw 0Ah ; retlw 0 ; 100 retlw 0 ; retlw 064h ; retlw 0 ; 1 000 retlw 03h ; retlw 0E8h ; retlw 0 ; 10 000 retlw 027h ; retlw 010h ; retlw 01h ; 100 000 retlw 086h ; retlw 0A0h ; retlw 0Fh ; 1 000 000 retlw 042h ; retlw 040h ; ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l Table for conversion BCD -> 7 segments l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 LEDTable addwf PCL,F ; W + PCL -> PCL retlw b'00111111' ; ..FEDCBA = '0' retlw b'00000110' ; .....CB. = '1' retlw b'01011011' ; .G.ED.BA = '2' retlw b'01001111' ; .G..DCBA = '3' retlw b'01100110' ; .GF..CB. = '4' retlw b'01101101' ; .GF.DC.A = '5' retlw b'01111101' ; .GFEDC.A = '6' retlw b'00000111' ; .....CBA = '7' retlw b'01111111' ; .GFEDCBA = '8' retlw b'01100111' ; .GF..CBA = '9' retlw b'10000000' ; H....... = '.' ;U賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽U ;U The main cycle entry point U ;U컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴U ;U Routine for conversion of 3-byte number into 7 digits U ;U複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複U Entry bsf STATUS,RP0 movlw b'00000000' movwf TRISB bcf STATUS,RP0 movlw 6*3-1 ; pointer to dec. table movwf Index ; 6*3-1 -> Index movlw 9 ; maximum of substractions movwf Count ; 9 -> Count clrf Help movlw 6 movwf LEDIndex Divide call Subc24 ; substract untill result is negative, btfsc STATUS,C ; add last substracted number goto Add24 ; next digit incf Help,F decf Count,F btfss STATUS,Z goto Divide movlw 3 subwf Index,F goto Next Add24 call Addc24 movlw 3 subwf Index,F Next movlw 9 movwf Count movlw LED1 ; LED1 -> W addwf LEDIndex,W ; LED1 + LEDIndex -> W movwf Temp decf Temp,F ; LEDIndex+LED1-1 -> TEMP movf Temp,W movwf FSR ; W -> FSR movf Help,W ; Help -> W clrf Help ; save result at LEDx movwf INDF ; W -> LED(6..1) decf LEDIndex,F movlw 1 addwf Index,W btfss STATUS,Z goto Divide movf LowB,W movwf LED0 ; the rest -> LED0 ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l Registers LED0..LED6 are filled with values l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 clrf TimerH clrf TMR0 nop nop clrf LEDIndex movf MTT,W ; set initial counter value movwf Index ; LF or UHF -> Index clrf INTCON ; global INT disable, TMR0 INT disable ; clear TMR0 overflow bite ;�袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴敲 ;s Start of the measurement: RA3 + RA4 set input s ;C袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴�L movlw b'00010000' ; all ports set L, RA4 set H movwf PORTA bsf STATUS,RP0 movlw b'00011000' ; RA0..RA2 output, RA3, RA4 input movwf TRISA bcf STATUS,RP0 ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l 7-step cycle of digits l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 LEDCycle movlw LED0 addwf LEDIndex,W ; LED1 + LEDIndex -> W movwf FSR ; W -> FSR movf INDF,W ; LED(0..6) -> W call LEDTable ; W contains segments movwf Temp ; test for decimal point movf MD,W subwf LEDIndex,W btfss STATUS,Z goto NoDot bsf Temp,7 ; common cathode.... NoDot movf Temp,W movwf PORTB ; segments -> PORTB movf LEDIndex,W ; LEDIndex -> W nop movwf PORTA ; digit number -> PORTA ;컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� btfss INTCON,2 ; Test for TMR0 overflow goto DoNothing incf TimerH,F ; YES! Increment SW counter bcf INTCON,2 ; clear overflow bite goto O_K DoNothing nop nop nop ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l The first timing loop 2+3*T1 procesor cycles l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 O_K movf TM1,W movwf Temp Pause decfsz Temp,F goto Pause nop ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l The end of one digit processing l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 incf LEDIndex,F movlw 7 ; is 7th? subwf LEDIndex,W btfss STATUS,Z goto LEDCycle ; next digit nop ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l The second timing loop 2+3*T2 procesor cycles l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 movf TM2,W movwf Temp Again decfsz Temp,F goto Again nop ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l The end of one 7-digits processing l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 clrf LEDIndex decfsz Index,F goto LEDCycle ; next 7 * LED nop ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l The third timing loop 2+9*T3+Z procesor cycles l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 movf TM3,W movwf Temp EndPause btfss INTCON,2 ; Final test for TMR0 overflow goto Nothing2Do incf TimerH,F bcf INTCON,2 goto Nx Nothing2Do nop nop nop Nx decfsz Temp,F goto EndPause nop nop ; Z times NOP (0..8) nop nop ;�袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴敲 ;s Stop of the measurement: RA3 set output RA4 set input s ;C袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴袴�L clrw movwf PORTB movlw b'00010000' ; RA0..RA3 = 0 movwf PORTA ; W -> PORTA bsf STATUS,RP0 movlw b'00010000' ; RA0..RA3 output movwf TRISA ; RA4 input bcf STATUS,RP0 btfsc INTCON,2 ; really final check incf TimerH,F bcf INTCON,2 ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l Analyse precounter and store counted value in registers l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 movf TMR0,W movwf MidB ; TMR0 -> MidB movf TimerH,W movwf HigB ; TimerH -> HigB clrf Temp CountIt incf Temp,F bsf PORTA,3 ; _| false impulz bcf PORTA,3 ; |_ bcf INTCON,2 movf TMR0,W ; actual TMR0 -> W bcf STATUS,Z subwf MidB,W btfsc STATUS,Z goto CountIt incf Temp,F comf Temp,F incf Temp,F incf Temp,W movwf LowB ;旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴z ;l Range switching according value on RB0 pin l ;R컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴훃 movlw b'00010111' ; set A0..A2 bites high movwf PORTA ; e.g. send "8" to decoder bsf STATUS,RP0 movlw b'00000001' ; set RB0 as input, the rest as output movwf TRISB bcf STATUS,RP0 btfsc PORTB,0 ; if 0. bit=1 then VHF-UHF goto SetUHF ; else low frequency movf T1,W ; fill registers with proper values movwf TM1 movf T2,W movwf TM2 movf T3,W movwf TM3 movf MT,W movwf MTT movf D,W movwf MD goto Entry SetUHF movf U1,W ; fill registers with proper values movwf TM1 movf U2,W movwf TM2 movf U3,W movwf TM3 movf UT,W movwf MTT movf UD,W movwf MD goto Entry ;U賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽賽U ;U The main cycle end U ;U複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複複U end