; File: top.asm ; Author: Gaspar Sinai ; Version: 2010-04-27 ; Copyright: Gaspar Sinai ; Top module for frequency counter ; ; gotchas: ; ; 1. PIC16F877A PortA5 is open collector. Needs a 3.9k pull-up resistor. ; 2. The display was two bright when driven with 25 mA / 5 = 5 mA. ; Change resistor from 180 Ohm to 270 Ohm. 17 mA / 5 = 3.3 mA ; 240mW ; Change resistor from 180 Ohm to 330 Ohm. 14 mA / 5 = 2.7 mA ; 200mW ; (*) Change resistor from 180 Ohm to 510 Ohm. 8 mA / 5 = 1.6 mA ; 115mW ; 510 Ohm is used because the blue led was very bright even with 330 Ohms. ; With 180 Ohms it was burning bright. ; RD1,2 is pulled up to 5V by 3.9K. There is a switch to ground for ; calibration (+/- 1 HHz steps of reference frequency.) #include "common.inc" #include "util.inc" #include "i2c.inc" ; XT_OSC external osciallator XT,HS ; WDT_OFF no watchdog timer ; WRT_OFF no prog memmory write protection ; CP_OFF no code protect ; CPD_OFF no code protect data ; BODEN_ON brown out reset ; PWRTE_OFF power up timer disabled ; LVP_OFF low voltage in-circuit serial programming disabled __CONFIG (_XT_OSC & _WDT_ON & _WRT_OFF & _CP_OFF & _CPD_OFF & _BODEN_ON & _PWRTE_OFF & _LVP_OFF) CounterI2CAddress equ H'21' ; The address of the counter CPLD ; We use double scan, but in fact a single scan will suffice ; 10 works for a single scan 10 digit display. ; DisplayDarkness equ .10 ; 5-20 - 5 is lightest. udata_shr ; bank0 and 1. SaveW res 1 ; Irq4 saves W here IntVarA res 1 ; Used by interrupt IntCounter res 1 ; Interrupt Counter udata SaveStatus res 1 ; Irq4 Saves STATUS here SavePCLATH res 1 ; Irq4 Saves PCLATH here SaveFSR res 1 ; Irq4 Saves FSR here Display res 9 ; 9 7+1 segments abcdef. LSB first. 9th digit is portD Led res 1 ; 1 LED at bit 0 BCDBuffer res 5 ; Packed BCD result buffer. DecimalPoint res 1 ; Nibble position of decimal poing in BCDBuffer. VarI res 1 ; general Purpose variable VarJ res 1 ; general Purpose variable VarK res 1 ; general Purpose variable VarBuffer res .10 ; general purpose buffer Mux res 1 ; Display Multipexer PortDState res 1 ; Port D last state. CalibrationData res 1 ; Calibration add/substract org 0 goto Main org 4 ; ; interrupt service ; ; Save registers movwf SaveW swapf STATUS,W clrf STATUS ; Point to bank 0 and clear all the flags movwf SaveStatus ; We have no paging, but I left it here for completness. ; You can save 4 cycles if you are in a pinch by commenting out ; the save PCLATH lines. movf PCLATH,W movwf SavePCLATH movf FSR,W movwf SaveFSR ; Interrupt handling banksel PIR1 btfsc PIR1,TMR2IF goto TimerInterrupt ReturnFromInterrupt: clrf STATUS ; Point to bank 0 and clear all the flags ; Restore registers movf SaveFSR,W movwf FSR movf SavePCLATH,W movwf PCLATH swapf SaveStatus,W movwf STATUS swapf SaveW,F swapf SaveW,W retfie TimerInterrupt: clrwdt clrf STATUS ; Point to bank 0 and clear all the flags BANKSEL PORTC ; PorrC[0,1,2,5] PortD[0] is digit select 0 movlw b'00000000' ; All digits off movwf PORTC BANKSEL PORTD movlw b'00000000' ; All digits off movwf PORTD ; Read Display[4-8] BANKSEL Mux ; Next multiplexer index incf IntCounter,F incf Mux,W addlw -DisplayDarkness ; valid values: 0-4. To make it darker we have 5. btfsc STATUS,C ; skip borrow movlw -DisplayDarkness addlw DisplayDarkness movwf Mux addlw Display+4 movwf FSR comf INDF,W ; 0 is on ; PortB[0-7] BANKSEL PORTB movwf PORTB ; Read Display[0-4] BANKSEL Mux movf Mux,W addlw Display movwf FSR comf INDF,W ; 0 is on ; PortA[0-5] BANKSEL PORTA movwf PORTA ; PortC[6-7] andlw b'11000000' movwf IntVarA ; Available in all banks - no need for it now. ; PorrC[0,1,2,5] is digit select 0 ; TODO, FIXME send digit selector 1 active. BANKSEL Mux movf Mux,W addlw 0 btfsc STATUS,Z bsf IntVarA,0 addlw -1 btfsc STATUS,Z bsf IntVarA,1 addlw -1 btfsc STATUS,Z bsf IntVarA,2 addlw -1 btfsc STATUS,Z bsf IntVarA,5 addlw -1 btfsc STATUS,Z goto IntPortD IntPortDBack: movf IntVarA,W BANKSEL PORTC movwf PORTC BANKSEL PIR1 bcf PIR1,TMR2IF goto ReturnFromInterrupt IntPortD: BANKSEL PORTD movlw 1 movwf PORTD goto IntPortDBack Main: ; ; Program starts here ; clrf STATUS ; Select bank 0 and clear all flags. clrf Mux ; Display Multipexer bsf OPTION_REG,NOT_RBPU ; Disable B pull-ups ; Min 7 max 33 ms WDT without prescaler bcf OPTION_REG,PS0 ; Prescaler WDT 0 bcf OPTION_REG,PS1 ; Prescaler WDT 0 bcf OPTION_REG,PS2 ; Prescaler WDT 0 bsf OPTION_REG,PSA ; WDT Source bcf OPTION_REG,T0CS ; Dont use T0CK1, we have this as port. ; ; Set up port directions ; PortA[0-5]PortC[67] is 8 segments of Display0-3 (abcdef.) 0=a ; PortB[0-8] is 8 segments of Display4-8 (abcdef.) 0=a ; PortC 4 bit [012][5] PortD[0] Digit Selector ; PortC-3 I2C SCL - set as input ; PortC-4 I2C SDA - set as input ; BANKSEL TRISA movlw b'00000000' ; 0 output movwf TRISA BANKSEL PORTA movlw b'11111111' ; off movwf PORTA BANKSEL TRISB movlw b'00000000' ; 0 output movwf TRISB BANKSEL PORTB movlw b'11111111' ; off movwf PORTB BANKSEL TRISC movlw b'00011000' ; 0 output movwf TRISC BANKSEL PORTC movlw b'00000000' ; digits off movwf PORTC BANKSEL TRISD movlw b'00000110' ; 0 output 1,2 is a switch to ground. movwf TRISD BANKSEL PORTD movlw b'00000000' ; 9th digit off movwf PORTD ; Initialize Display interrupt BANKSEL T2CON clrf T2CON ; Clear prescaler bsf T2CON,TMR2ON ; Enable timer2 bsf T2CON,T2CKPS0 bcf T2CON,T2CKPS1 ; 1:4 prescaler 4 MHz clock -> 250kHz BANKSEL PR2 movlw .124 ; Divide by 125 for 2kHz movwf PR2 ; Note: we dont enable SSPIE for I2C BANKSEL PIE1 clrf PIE1 bsf PIE1,TMR2IE ; Enable the TMR2 to PR2 match interrupt BANKSEL PIR1 bcf PIR1,TMR2IF ; Clear timer2 interrupt flag BANKSEL INTCON bsf INTCON,PEIE ; Peripheral Interrupt Enable bsf INTCON,GIE ; Global Interrupt Enable call SayHello ; Timer interrupt for display multiplexing ; I2C clrf STATUS ; Select bank 0 and clear all flags. movlw .100 call WaitWms MainLoopTmp: clrf STATUS ; Select bank 0 and clear all flags. ; FIXME ; goto MainLoopTmp ; SGC movlw .1 ; Synchronize to display call WaitWms call I2CInit movlw CounterI2CAddress movwf I2CAddress MeasureLoop: call ClearCalibrationData movlw b'01000000' ; Stop measuring movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWrite movlw .50 call WaitWms MainWaitReady: BANKSEL PORTD movf PORTD,W andlw b'00000110' call ReadCalibrationData movlw b'11000000' ; Start measurement, Read status movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead iorlw 0 btfss STATUS,Z goto DeviceNotFound btfss I2CData,0 ; Skip ready measure goto MainWaitReady btfsc I2CData,1 ; Skip no underflow goto MainUnderflow ; ; When there is a measurement made, we can update ; the calibration data if user pressed the calibration switches. ; call ReadCalibrationData iorlw 0 btfss STATUS,Z call TimeBaseAdd ; Modify our timebase with calibration data ; ; Put the reference frequency to multiplicand ; movlw 0 call TimeBaseRead BANKSEL AritBuffer movwf AritBuffer+0 movlw 1 call TimeBaseRead BANKSEL AritBuffer movwf AritBuffer+1 movlw 2 call TimeBaseRead BANKSEL AritBuffer movwf AritBuffer+2 movlw 3 call TimeBaseRead BANKSEL AritBuffer movwf AritBuffer+3 ; Read the measured cycles, calculate frequency ; 0..3 cnt_x. Keep measure bit 1. movlw b'10000000' iorlw 0 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+8 movlw b'10000000' iorlw 1 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+9 movlw b'10000000' iorlw 2 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+.10 movlw b'10000000' iorlw 3 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+.11 call Multiply ; 4..7 cnt_r movlw b'10000000' iorlw 4 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+8 movlw b'10000000' iorlw 5 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+9 movlw b'10000000' iorlw 6 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+.10 movlw b'10000000' iorlw 7 movwf I2CData movlw .1 ; Synchronize to display call WaitWms call I2CWriteRead movf I2CData,W movwf AritBuffer+.11 call CalculateFrequency call BCDBufferToDisplay movlw .2 call WaitWms goto MeasureLoop DeviceNotFound: call I2CError goto MeasureLoop MainUnderflow: clrf Led movlw b'10111111' ; 0. movwf Display+8 movlw b'00111111' ; 0 movwf Display+7 movlw b'00111111' ; 0 movwf Display+6 movlw b'00111111' ; 0 movwf Display+5 movlw b'00111111' ; 0 movwf Display+4 movlw b'00111111' ; 0 movwf Display+3 movlw b'00111111' ; 0 movwf Display+2 movlw b'00111111' ; 0 movwf Display+1 movlw b'00111111' ; 0 movwf Display+0 movlw .100 call WaitWms goto MeasureLoop CalculateFrequency: ; Call divide and calculate ; BCDBuffer and DecimalPoint call Divide call ToBCDInteger ; Copy DecNumber -> VarBuffer movf DecNumber+0,W movwf VarBuffer+0 movf DecNumber+1,W movwf VarBuffer+1 movf DecNumber+2,W movwf VarBuffer+2 movf DecNumber+3,W movwf VarBuffer+3 movf DecNumber+4,W movwf VarBuffer+4 movf DecNumber+5,W movwf VarBuffer+5 movf DecNumber+6,W movwf VarBuffer+6 movf DecNumber+7,W movwf VarBuffer+7 movf DecNumber+8,W movwf VarBuffer+8 movf DecNumber+9,W movwf VarBuffer+9 call DivideFraction call ToBCDFraction clrf BCDBuffer clrf BCDBuffer+1 clrf BCDBuffer+2 clrf BCDBuffer+3 clrf BCDBuffer+4 ; Shift DecNumber (10 bytes = 20 nibbles) into BCDBuffer (4 bytes = 8 nibbles) movlw -.20 ; Initial decimal point nibble position. movwf DecimalPoint movlw .20+8 ; max shift left. Leading zero kept for units. movwf VarI MainIntShiftLoop1: movlw 4 ; 4 bit in a nibble movwf VarJ MainIntShiftLoop2: bcf STATUS,C rlf DecNumber+0,F rlf DecNumber+1,F rlf DecNumber+2,F rlf DecNumber+3,F rlf DecNumber+4,F rlf DecNumber+5,F rlf DecNumber+6,F rlf DecNumber+7,F rlf DecNumber+8,F rlf DecNumber+9,F rlf VarBuffer+0,F rlf VarBuffer+1,F rlf VarBuffer+2,F rlf VarBuffer+3,F rlf VarBuffer+4,F rlf VarBuffer+5,F rlf VarBuffer+6,F rlf VarBuffer+7,F rlf VarBuffer+8,F rlf VarBuffer+9,F rlf BCDBuffer+0,F rlf BCDBuffer+1,F rlf BCDBuffer+2,F rlf BCDBuffer+3,F rlf BCDBuffer+4,F decfsz VarJ,F goto MainIntShiftLoop2 incf DecimalPoint,F ; Check if there is any nonzero most significant digit. movf BCDBuffer+4,W andlw 0x0f btfss STATUS,Z goto MainIntShiftEnd decfsz VarI,F goto MainIntShiftLoop1 MainIntShiftEnd: return BCDBufferToDisplay: ; ; Display what is in BCDBuffer ; A Decimal point will be displayed at DecimalPoint ; movf BCDBuffer+0,W call Get7SegmentPattern movwf Display+0 movf DecimalPoint,W btfsc STATUS,Z bsf Display+0,7 movwf VarI swapf BCDBuffer+0,W call Get7SegmentPattern movwf Display+1 decf VarI,F btfsc STATUS,Z bsf Display+1,7 movf BCDBuffer+1,W call Get7SegmentPattern movwf Display+2 decf VarI,F btfsc STATUS,Z bsf Display+2,7 swapf BCDBuffer+1,W call Get7SegmentPattern movwf Display+3 decf VarI,F btfsc STATUS,Z bsf Display+3,7 movf BCDBuffer+2,W call Get7SegmentPattern movwf Display+4 decf VarI,F btfsc STATUS,Z bsf Display+4,7 swapf BCDBuffer+2,W call Get7SegmentPattern movwf Display+5 decf VarI,F btfsc STATUS,Z bsf Display+5,7 movf BCDBuffer+3,W call Get7SegmentPattern movwf Display+6 decf VarI,F btfsc STATUS,Z bsf Display+6,7 swapf BCDBuffer+3,W call Get7SegmentPattern movwf Display+7 decf VarI,F btfsc STATUS,Z bsf Display+7,7 movf BCDBuffer+4,W call Get7SegmentPattern movwf Display+8 decf VarI,F btfsc STATUS,Z bsf Display+8,7 incf DecimalPoint,W btfss STATUS,Z return ; MHz.KHz.Hz on 8 digits. We have 9 digits now. ; bsf Display+2,7 ; bsf Display+5,7 return Get7SegmentPattern andlw h'0f' movwf VarJ movlw high(PatternTable) movwf PCLATH movf VarJ,W addlw low (PatternTable) btfsc STATUS,C incf PCLATH,F movwf PCL PatternTable: retlw b'00111111' ; 0 retlw b'00000110' ; 1 retlw b'01011011' ; 2 retlw b'01001111' ; 3 retlw b'01100110' ; 4 retlw b'01101101' ; 5 retlw b'01111101' ; 6 retlw b'00000111' ; 7 retlw b'01111111' ; 8 retlw b'01101111' ; 9 retlw b'01110111' ; A retlw b'01111100' ; b retlw b'00111001' ; C retlw b'01011110' ; d retlw b'01111001' ; E retlw b'01110001' ; F I2CError: clrf Led movlw b'01110001' ; F movwf Display+8 movlw b'00000100' ; i movwf Display+7 movlw b'01011011' ; 2 movwf Display+6 movlw b'01011000' ; c movwf Display+5 movlw b'01111001' ; E movwf Display+4 movlw b'01010000' ; r movwf Display+3 movlw b'01010000' ; r movwf Display+2 movlw b'01011100' ; o movwf Display+1 movlw b'01010000' ; r movwf Display+0 return SayHello: clrf Led movlw b'11101101' ; S. movwf Display+8 movlw b'01101110' ; Y movwf Display+7 movlw b'00111110' ; U movwf Display+6 movlw b'01110011' ; P movwf Display+5 movlw b'00111110' ; U movwf Display+4 movlw b'01000000' ; - movwf Display+3 movlw b'01110001' ; F movwf Display+2 movlw b'10000110' ; 1. movwf Display+1 movlw b'00111111' ; 0 movwf Display+0 return WaitWms: ; Wait W ms. It is waiting W millisedonds if interrupt is every ; millisecond. Currenly it waits only 500us as interrupt is 2KHz now. BANKSEL IntCounter WaitWmsLoop: addlw 0 btfsc STATUS,Z return addlw -1 btfsc IntCounter,0 goto WaitWms1 WaitWms0: btfss IntCounter,0 goto WaitWms0 goto WaitWmsLoop WaitWms1: btfsc IntCounter,0 goto WaitWms1 goto WaitWmsLoop ClearCalibrationData: ; ; Clear calibration data ; BANKSEL PORTD movf PORTD,W andlw b'00000110' clrf STATUS ; Select bank 0 and clear all flags. movwf PortDState clrf CalibrationData ReadCalibrationData: ; ; Update calibration data and read it into W ; BANKSEL PORTD btfss PORTD,1 ; 0 active - count up goto ReadCalibration1 btfss PORTD,2 ; 0 active - count down goto ReadCalibration2 clrf STATUS ; Select bank 0 and clear all flags. movlw b'00000110' movwf PortDState movf CalibrationData,W return ReadCalibration1: ; Add 1 to CalibrationData if PortDState,1 is set BANKSEL PortDState btfsc PortDState,1 incf CalibrationData,F bcf PortDState,1 movf CalibrationData,W return ReadCalibration2: ; Substract 1 from CalibrationData if PortDState,2 is set BANKSEL PortDState btfsc PortDState,2 decf CalibrationData,F bcf PortDState,2 movf CalibrationData,W return end