; ------------------------------------------------------------------------ ; FILE : LCDDIGI.ASM * ; CONTENTS : Simple low-cost 7-digit digital scale using a PIC16F84 * ; COPYRIGHT: Peter Halicky OM3CPH * ; AUTHOR : Peter Halicky OM3CPH & Peter Halicky Jr., OM2PH * ; PCB : Tibor Madarasz OM2ATM * ;-------------------------------------------------------------------------- ; E-Mail: peter@halicky.sk ; ; Bratislava, Slovakia, December 1998, revised & debugged Januar, 2000 ;-------------------------------------------------------------------------- ; This is 7-digit digital scale counting up to 35 MHz. The decimal point ; is after MHz digit. ; ; It adds or substracts RF according signal level at RA2: ; +5V - adds RF ; disconnected - substracts RF ; ; Hardware is very simple: ; ; It contains : PIC 16F84 ; 1 NPN low power HF Si transistor, ; 16 character (2x8) in 1 Line LCD display, ; Xtal 1..10 MHz, ; some resistors, capacitors and 2 Si switching diodes... ; (see schematic in lcd_digi.pcx) ; Note: ; LCD display is 16 character in 1 line LCD display PVC160101PTN which ; seems to be compatible with TWO LINES HITACHI LCD display, exept ; that it has only 8 characters in 1 line. ; ; The counter uses internal prescaler of PIC as low byte of counter, ; TMR0 as middle byte and some register as high byte of counter. ; ; Some ideas were taken from "Simple low-cost digital frequency meter ; using a PIC 16C54" (frqmeter.asm) ; written by James Hutchby, MadLab Ltd. 1996 ; LCD interfacing was taken from AN587 and mainly from LCD.ASM written ; by Peter Ouwehand. ; ------------------------------------------------------------------------ ; ; This software is free for private usage. It was created for HAM radio ; community members. Commercial exploatation is allowed only with permission ; of authors. ; ; ------------------------------------------------------------------------ ; ; The measuring period is 100 000 us. ; Procesor cycle is T = 4/Fx [us,MHz], fx is Xtal frequency ; ; Number of procesor cycles per measuring period: ; ; N = 100 000/T procesor cycles ; N = Fx * 100 000/4 = 25 000 x Fx ; ; The main steps of measuring period: ; ; 1. decode 3-byte value into 7 decimal numbers, ; 2. decode decimal value of digit to chars, ; 3. set decimal point if needed, ; 4. output to PORTB (LCD), ; 5. start measurement, ; 6. test TMR0 overflow bite, if YES increase TimerH, ; 7. goto 5 until measuring period is done, ; 8. stop measurement, ; 9. shift out precounter content, ; 10. Add/substract RF according signal from optocoupler, ; 11. goto 1 ; ; ------------------------------------------------------------------------ ; ; Total timing formula: N = 25 000 * Fx = ((9*T1+4)*T2+4)*T3+5+9*T4+Z ; ; N = 25 000 * Fx [MHz] ; ; Example: Fx = 4 MHz ; ; N = 25 000 * 4 = 100 000 ; N = 25 000 * Fx = ((9*T1+4)*T2+4)*T3+5+9*T4+Z ; ; ------------------------------------------------------------------------ include ; ------------------------------------------------------------------------ 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 LCD_TEMP equ 016h ; LCD subroutines internal use TimerH equ 017h ; the highest 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 R1 equ 01Eh ; Timing counters R2 equ 01Fh R3 equ 020h ; ------------------------------------------------------------------------ ; LCD variables ; ------------------------------------------------------------------------ ;FREQ EQU .8 ; Xtal frequency in MHz DELAY15 EQU .20 ; (HIGH((4*15000/770/FREQ))+1 LINE0 equ 0 LINE1 equ 040h ; PORTA bits E equ 2 ; LCD Enable control line R_W equ 1 ; LCD Read/Write control line RS equ 0 ; LCD Register-Select control line ; ------------------------------------------------------------------------ include ; timing loop values ; ------------------------------------------------------------------------ org 0 Start clrf STATUS ; Do initialization, Select bank 0 clrf INTCON ; Clear int-flags, Disable interrupts clrf PCLATH ; Keep in lower 2KByte clrf PORTA ; ALL PORT output should output Low. clrf PORTB clrf Index clrf LEDIndex clrf LED0 clrf LED1 clrf LED2 clrf LED3 clrf LED4 clrf LED5 clrf LED6 clrf LowB clrf MidB clrf HigB bsf STATUS,RP0 movlw b'00010000' ; RA0..RA3 outputs movwf TRISA ; RA4 input movlw b'00000000' ; RB0..RB7 outputs movwf TRISB bsf OPTION_REG,NOT_RBPU clrwdt ; Disable PORTB pull-ups movlw b'10100111' ; Prescaler -> TMR0, movwf OPTION_REG ; 1:256, rising edge bcf STATUS,RP0 ; ; Initilize LC-Display Module ; Busy-flag is not yet valid clrf PORTA ; ALL PORT output should output Low. movlw DELAY15 ; Wait for 15ms for LCD to get powered up movwf R1 clrf R2 LCycle decfsz R2,F goto LCycle ; 3*256 decfsz R1,F ; 3*256+1 goto LCycle ;(3*256+2)*R1=770*R1 in procesor cycles movlw B'00111000' ; 8-bit-interface, 2-lines call PutCMD movlw B'00001000' ; disp.off, curs.off, no-blink call PutCMD movlw 1 ; LCD clear call PutCMD movlw B'00001100' ; disp.on, curs.off call PutCMD movlw B'00000110' ; auto-inc (shift-cursor) call PutCMD goto Go ;************************************************************************ ; LCD Module Subroutines ;************************************************************************ ; Busy: Returns when LCD busy-flag is inactive ; ; PORTA returns as RA0..RA2 output, RA3,RA4 input ; PORTB returns as full output ;======================================================================== Busy bsf STATUS,RP0 ; Select Register page 1 movlw 0FFh ; Set PORTB for input movwf TRISB movlw b'00011000' ; PORTA should be set RA0..RA2 output movwf TRISA ; RA3,RA4 input bcf STATUS,RP0 ; Select Register page 0 bcf PORTA,RS ; Set LCD for command mode bsf PORTA,R_W ; Setup to read busy flag bsf PORTA,E ; LCD E-line High movf PORTB,W ; Read busy flag + DDram address bcf PORTA,E ; LCD E-line Low andlw 080h ; Check Busy flag, High = Busy btfss STATUS,Z goto Busy bcf PORTA,R_W bsf STATUS,RP0 ; Select Register page 1 movlw 0 movwf TRISB ; Set PORTB for output bcf STATUS,RP0 ; Select Register page 0 return ;======================================================================== ; PUTCHAR Sends character to LCD, Required character must be in W ;======================================================================== PutCHAR movwf LCD_TEMP ; Character to be sent is from W saved call Busy ; Wait for LCD to be ready ; Busy routine sets PORTA&PORTB adequately bcf PORTA,R_W ; Set LCD in read mode bsf PORTA,RS ; Set LCD in data mode bsf PORTA,E ; LCD E-line High movf LCD_TEMP,W ; Restore character into W movwf PORTB ; Send data to LCD bcf PORTA,E ; LCD E-line Low return ;======================================================================== ; PutCMD Sends command to LCD, Required command must be in W ;======================================================================== PutCMD movwf LCD_TEMP ; Command to be sent is from W saved call Busy ; Wait for LCD to be ready ; Busy routine sets PORTA&PORTB adequately bcf PORTA,R_W ; Set LCD in read mode bcf PORTA,RS ; Set LCD in command mode bsf PORTA,E ; LCD E-line High movf LCD_TEMP,W movwf PORTB ; Send data to LCD bcf PORTA,E ; LCD E-line Low return ;************************************************************************ ; End of LCD Module Subroutines ;************************************************************************ ; Numeric routines ;------------------------------------------------------------------------ ; 3 byte substraction of the constant from the table which sets carry if ; result is negative ;------------------------------------------------------------------------ Subc24 clrf TEMP ; it will TEMPorary save C 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 C 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 which sets carry if ; result overflows ; ------------------------------------------------------------------------ Addc24 clrf TEMP ; register for TEMPorary storage of C 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 ;------------------------------------------------------------------------ ; Tables for 3 byte constants ;------------------------------------------------------------------------ ; Table of decades ;------------------------------------------------------------------------ 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 ; ;------------------------------------------------------------------------ ; Table for RF shift - it is needed in the case of digiscale ; Example: 10.7 MHz is set as 1 070 000 = 10 53 B0 hex ; Note: direct definition using compiler directive is possible too... ;------------------------------------------------------------------------ IFTable addwf PCL,F include ;************************************************************************ ; Entry point for main cycle ;************************************************************************ ;------------------------------------------------------------------------ ; Routine for the conversion of 3 byte number into 7 decimal numbers ;------------------------------------------------------------------------ Go 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 03h 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 ;------------------------------------------------------------------------- ; registers LED0..LED6 are filled with values - ready to be displayed ;------------------------------------------------------------------------- movlw 6 movwf LEDIndex movlw LINE0 iorlw 080h ; Position cursor leftmost on first line call PutCMD LEDCycle movlw LED0 ; LED0 -> W addwf LEDIndex,W ; LED1 + LEDIndex -> W movwf FSR ; W -> FSR movf INDF,W ; LED(0..6) -> W iorlw 030h call PutCHAR ; Display character movlw 5 ; test for decimal point bsf STATUS,Z subwf LEDIndex,W btfss STATUS,Z goto NoDot movlw '.' ; this can be ' ' or ',' ...... call PutCHAR ; Display character NoDot decfsz LEDIndex,F goto LEDCycle ; continue with next number movlw LED0 ; LED0 -> W addwf LEDIndex,W ; LED0 + LEDIndex -> W movwf FSR ; W -> FSR movf INDF,W ; [FSR] -> W iorlw 030h call PutCHAR ; Display character movlw LINE1 ; continue at right half of display iorlw 080h ; Function set call PutCMD ; Position cursor leftmost on first line movlw ' ' call PutCHAR ; Display character movlw 'M' call PutCHAR ; Display character movlw 'H' call PutCHAR ; Display character movlw 'z' call PutCHAR ; Display character movlw LINE0 iorlw 080h ; Function set call PutCMD ;------------------------------------------------------------------------- ; It is time to prepare new measuring cycle ;------------------------------------------------------------------------- clrf TimerH clrf TMR0 nop ; it is SUGGESTED... nop clrf LEDIndex movlw T1 ; set initial counter values movwf R1 movlw T2 movwf R2 movlw T3 movwf R3 clrf INTCON ; global INT disable, TMR0 INT disable ; clear TMR0 overflow bite ; ------------------------------------------------------------------------ ; Start measurement: RA3 + RA4 set input ; ------------------------------------------------------------------------ movlw b'00010000' ; all ports set L, RA4 set H movwf PORTA bsf STATUS,RP0 movlw b'00011111' ; RA0..RA4 input movwf TRISA bcf STATUS,RP0 ; ------------------------------------------------------------------------- ; It is opened now... ; ------------------------------------------------------------------------- Cycle btfss INTCON,2 ; 1 Test for TMR0 overflow goto Nothing ; 3 incf TimerH,F ; 3 bcf INTCON,2 ; 4 goto Nxt ; 6 Nothing nop ; 4 nop ; 5 nop ; 6 Nxt decfsz R1,F ; 7 goto Cycle ; 9 movlw T1 ; 9*T1 movwf R1 ; 9*T1+1 decfsz R2,F ; 9*T1+2 goto Cycle ; 9*T1+4 movlw T2 ;(9*T1+4)*T2 movwf R2 ;(9*T1+4)*T2+1 decfsz R3,F ;(9*T1+4)*T2+2 goto Cycle ;(9*T1+4)*T2+4 ; ------------------------------------------------------------------------ ; Final test for TMR0 overflow ; ------------------------------------------------------------------------ movlw T4 ;((9*T1+4)*T2+4)*T3 movwf Help ;((9*T1+4)*T2+4)*T3+1 Cycle2 btfss INTCON,2 ; 1 goto Not2Do ; 3 incf TimerH,F ; 3 bcf INTCON,2 ; 4 goto Nx ; 6 Not2Do nop ; 4 nop ; 5 nop ; 6 Nx decfsz Help,F ; 7 goto Cycle2 ; 9 nop ; nop ; X times fine tuning nops ; nop ;((9*T1+4)*T2+4)*T3+1+9*T4+X include ; ------------------------------------------------------------------------ ; Stop the measurement ; ------------------------------------------------------------------------ clrw ; 1 movwf PORTB ; 2 movlw b'00010000' ; 3 RA0..RA3 = 0 movwf PORTA ; 4 W -> PORTA ;((9*T1+4)*T2+4)*T3+9*T4+X+5 bsf STATUS,RP0 ; 4 movlw b'00010111' ; 5 RA3 output movwf TRISA ; 6 RA0..RA2,RA4 input bcf STATUS,RP0 ; btfsc INTCON,2 ; really final check incf TimerH,F bcf INTCON,2 ; ------------------------------------------------------------------------ ; Analyse precounter and store counted value in registers ; ------------------------------------------------------------------------ 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 ; ------------------------------------------------------------------------ ; Frequency shift according value on RB0 pin ; Both routines are simplified Subc24 and Addc24 routines ; ------------------------------------------------------------------------ movlw b'00010000' movwf PORTA bsf STATUS,RP0 movlw b'00000100' ; set RA2 as input movwf TRISA bcf STATUS,RP0 btfss PORTA,E goto SubMF goto MFAdd ; ------------------------------------------------------------------------ ; First it must be checked which number is larger, than they are flipped ; if needed, than SUBSTRACT SMALLER from LARGER... ; Temporary are used nonused registers LED0..LED6 ; ------------------------------------------------------------------------ SubMF movlw 0 call IFTable bsf STATUS,C ; set C flag bcf STATUS,Z ; clear Z flag subwf HigB,W ; HigB - W -> W btfss STATUS,C ; if negative result (W>HigB) goto Change ; flip numbers btfss STATUS,Z ; if result=0 continue goto SetNmbrs ; else substract movlw 1 ; test next byte call IFTable bcf STATUS,Z ; clear Z flag bsf STATUS,C ; set C flag subwf MidB,W ; MidB - W -> W btfss STATUS,C ; if negative result (W>MidB) goto Change ; flip numbers btfss STATUS,Z ; if ZERO continue goto SetNmbrs ; else substract movlw 2 ; else continue with next byte call IFTable bsf STATUS,C subwf LowB,W ; LowB - W -> W btfss STATUS,C ; if result is negative(W>LowB) goto Change ; flip numbers goto SetNmbrs ; else substract Change movlw 0 ; prepare substraction MF - F call IFTable movwf LED0 ; highest byte MF to LED0 movf HigB,W movwf LED4 ; highest freq. byte to LED4 movlw 1 call IFTable movwf LED1 ; middle to LED1 movf MidB,W movwf LED5 ; MidB -> LED5 movlw 2 call IFTable movwf LED2 ; LowMF -> LED2 movf LowB,W movwf LED6 ; LowB -> LED6 goto MFSub SetNmbrs movlw 0 ; prepare substraction F - MF call IFTable movwf LED4 ; HighMF -> LED4 movf HigB,W movwf LED0 ; HighB -> LED0 movlw 1 call IFTable movwf LED5 ; MiddleMF -> LED5 movf MidB,W movwf LED1 ; MidB -> LED1 movlw 2 call IFTable movwf LED6 ; LowMF -> LED6 movf LowB,W movwf LED2 ; LowB -> LED2 ; ------------------------------------------------------------------------ ; Registers are ready, continue with substraction ; ------------------------------------------------------------------------ MFSub movf LED6,W bsf STATUS,C ; set C subwf LED2,F ; LED2 - LED6 -> LED2 btfsc STATUS,C goto S1 bsf STATUS,C movlw 1 subwf LED1,F btfsc STATUS,C goto S1 bsf STATUS,C movlw 1 subwf LED0,F btfsc STATUS,C goto S1 S1 movf LED5,W bsf STATUS,C subwf LED1,F ; LED1 - LED5 -> LED1 btfsc STATUS,C goto S2 bsf STATUS,C movlw 1 subwf LED0,F ; decrement LED0 btfsc STATUS,C goto S2 S2 movf LED4,W subwf LED0,F ; LED0 - LED4 -> LED0 ; ---------------------------------------------------------------------- ; Substraction is finished, now store result to frequency registers ; ---------------------------------------------------------------------- movf LED0,W movwf HigB movf LED1,W movwf MidB movf LED2,W movwf LowB goto ToMFEnd MFAdd movlw 2 call IFTable bcf STATUS,C addwf LowB,F btfss STATUS,C goto AddMF2 bcf STATUS,C movlw 1 addwf MidB,F btfss STATUS,C goto AddMF2 bcf STATUS,C movlw 1 addwf HigB,F btfss STATUS,C goto AddMF2 AddMF2 movlw 1 call IFTable bcf STATUS,C addwf MidB,F btfss STATUS,C goto AddMF3 bcf STATUS,C movlw 1 addwf HigB,F btfss STATUS,C goto AddMF3 AddMF3 clrw call IFTable addwf HigB,F ToMFEnd goto Go ; start new cycle ; ------------------------------------------------------------------------ end