;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;::;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; ; Program: DS18B20 Digital Thermometer with .1 Degree Increments ; ; Author: Jake Sutherland ; ; Start Date: Sunday 16th May 2010 ; ; Finish Date: Wednesday 20th October 2010 ; ; ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;::;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; LIST P=PIC16F628A INCLUDE P16F628A.INC __CONFIG (0x3F38); cblock 20h TEMPHI TEMPLO HUNS_ISR TENS_ISR ONES_ISR HUNS ONES TENS DIGIT DELAYGPR1 W_ISR S_ISR P_ISR F_ISR FLAGS SHIFT COUNT INDEX COLUMN TEMP N ENDC ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;::;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ; ; ; PIC16F628A Microcontroller ; ; ____ ____ ; ; LED 7 Segment 10's CC VREF/AN2/RA2 -| 1 - 18 |- RA1/AN1 LED 7 Segment 1's CC ; ; LED 7 Segment 100's CC CPM1/AN3/RA3 -| 2 17 |- RA0/AN0 LED 7 Segment .1's CC ; ; DS18B20 I/O CMP2/T0CKI/RA4 -| 3 16 |- RA7/OSC1/CLKIN ; ; VPP/MCLR/RA5 -| 4 15 |- RA6/OSC2/CLKOUT ; ; VSS -| 5 14 |- VDD ; ; Segment DP INT/RB0 -| 6 13 |- RB7/T1OSC1/ICSPDAT Segment B ; ; Segment C DT/RX/RB1 -| 7 12 |- RB6/T1OSCO/T1CLKI/ICSPCLK Segment A ; ; Segment D CK/TX/RB2 -| 8 11 |- RB5 Segment F ; ; Segment E CCP1/RB3 -|_9____10_|- RB4/PGM Segment G ; ; ; ; ; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;::;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ORG H'000' ; Processor reset vector location. On power up, the program jumps here GOTO SETUP ; ORG H'004' ; Interrupt vector location. When an Interupt occurs, the program jumps here ; (Thanks Mike, K8LH for this ISR routine. Contact via Electro-Tech-Online.com) ; SAVE MOVWF W_ISR ; Save W to W_ISR SWAPF STATUS, W ; Use SWAPF instruction so status bits don't change MOVWF S_ISR ; Save Status to S_ISR CLRF STATUS ; Switch to Bank 0 MOVF PCLATH, W ; MOVE PCLATH to W register MOVWF P_ISR ; Save PCLATH to P_ISR CLRF PCLATH ; Force page 0 MOVF FSR, W ; MOVE FSR to W register MOVWF F_ISR ; Save FSR to F_ISR TRIGER BSF PORTA,0 BSF PORTA,1 BSF PORTA,2 DANIE_B CLRF PORTB ; Blank the display MOVFW DIGIT ADDLW HUNS_ISR ; Add 'Digit' to 'HUNS' GPR address MOVWF FSR ; FSR = HUNS + (0forHUNS, 1forTENS, 2forONES & 3forTENTHS) as they are in sequencial order in RAM MOVF INDF, W ; W register now holds BCD Number Pointer for corresponding digit to be CALL TABLE MOVWF PORTB INCF DIGIT, F ; Increment digit jump pointer (used when indirect addressing above) BCF STATUS,Z MOVFW DIGIT SUBLW .3 BTFSC STATUS,Z CLRF DIGIT DANIE_A MOVFW INDEX ADDWF COLUMN,W CALL TABLE ANDWF PORTA,F INCF INDEX,F BCF STATUS,Z MOVFW INDEX ADDWF COLUMN,W SUBLW .15 BTFSC STATUS,Z CLRF INDEX ; RESTORE BCF PIR1, TMR2IF ; Clear TMR2 interrupt flag while still in Bank 0 MOVF F_ISR, W ; MOVE F_ISR to W MOVWF FSR ; Restore FSR MOVF P_ISR, W ; MOVE P_ISR to W MOVWF PCLATH ; Restore PCLATH SWAPF S_ISR, W ; Undo previous SWAPF, place result in W MOVWF STATUS ; Restore STATUS SWAPF W_ISR, F ; Use SWAPF instruction so status bits don't change SWAPF W_ISR, W ; Undo previous SWAPF and restore W register RETFIE ; Return From Interrupt TABLE ; This routine assigns on/off arrangement to the 7 Segment Display addwf PCL,F ; Содержимое счетчика команд PC увеличивается retlw b'00111111' ; ..FEDCBA = 0 Происходит скачек по таблице retlw b'00000110' ; .....CB. = 1 на строку со значением, retlw b'01011011' ; .G.ED.BA = 2 записанным в аккумуляторе, retlw b'01001111' ; .G..DCBA = 3 и далее - возврат по стеку. 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'01101111' ; .GF.DCBA = 9 RETLW B'00000000' ; 10 -|-|-|-|-|-|-|- BLANK RETLW B'01000000' ; 11 -|-|-|G|-|-|-|- - RETLW B'11111011'; 12 RETLW B'11111101'; 13 RETLW B'11111110'; 14 RETURN SETUP ; This rountine sets up the Microcontroller's Inputs and Outputs MOVLW H'07' ; Turn Comparators off and enable pins for I/O functions MOVWF CMCON ; BSF STATUS, RP0 ; Bank 1 CLRF TRISA ; CLRF TRISB ; RB<7:0> Outputs BCF STATUS, RP0 ; Bank 0 CLRF PORTA CLRF PORTB MOVLW .12 MOVWF COLUMN CLRF DIGIT CLRF INDEX CLRF TMR2 ; Clear TMR2 register BSF STATUS, RP0 ; Bank 1 MOVLW B'00000010' ; 00000010 MOVWF PIE1 ; -------0 Disable TMR1IE - TMR1 Overflow Interrupt Enable bit ; ------1- Enable TMR2IE - TMR2 to PR2 Match Interrupt Enable bit ; -----0-- Disable CCP1IE - CCP1 Interrupt Enable bit ; ----X--- Unused ; ---0---- Disable TXIE - USART Transmit Interrupt Enable bit ; --0----- Disable RCIE - USART Receive Interrupt Enable bit ; -0------ Disable CMIE - Comparator Interrupt Enable bit ; 0------- Disable EEIE - EE Write Complete Interrupt Enable bit BCF STATUS, RP0 ; Bank 0 CLRF PIR1 ; Clear Peripheral Interrupt Flags MOVLW B'00000000' ; 00000001 MOVWF T2CON ; ------01 Prescale 1:4 ; -----0-- TMR2 OFF ; -0000--- Postscale 1:1 ; 0------- Unused BSF STATUS, RP0 ; Bank 1 MOVLW D'250' ; MOVWF PR2 ; Interrupt every 0.001s or 1mS BCF STATUS, RP0 ; Bank 0 BSF INTCON, GIE ; Enable Global Interrupts BSF INTCON, PEIE ; Enable Peripheral Interrupts BSF T2CON, TMR2ON ; Start TMR2 GET_TEMP CALL DS18B20_RESET MOVLW H'CC' ; Skiprom CALL DS18B20_WRITE_BYTE ; Skiprom MOVLW H'44' ; Convert T CALL DS18B20_WRITE_BYTE ; Convert T CALL DS18B20_READ_BIT ; Initiate Read Time Slots BTFSS STATUS, C ; DS18B20 transmits a 0 while the temperature conversion is in progress and a 1 when the conversion is done. GOTO $-D'2' CALL DS18B20_RESET ; Reset MOVLW H'CC' ; Skiprom CALL DS18B20_WRITE_BYTE ; Skiprom MOVLW H'BE' ; Read Scratchpad CALL DS18B20_WRITE_BYTE ; Read Scratchpad CALL DS18B20_READ_BYTE ; Move Scrachpad Byte 0 to W MOVWF TEMPLO ; Store in TEMPLO GPR CALL DS18B20_READ_BYTE ; Move Scrachpad Byte 1 to W MOVWF TEMPHI ; Store in TEMPHI GPR TEST_IF_NEGATIVE BCF FLAGS, 1 ; Clear Negative Flag BTFSS TEMPHI, 7 ; Test Negative Flag. If 1, Temperature is Negative GOTO REARRANGE_NIBBLES ; NOT Negative, skip over next 6 instructions (Don't Invert & + 1 (2's Complement)) ; Invert & + 1 ; EXAMPLE Negative Temperature TEMPHI = 1111 1110 TEMPLO = 0110 1110 = -25.1250 (see datasheet) BSF FLAGS, 1 ; Set Negative Flag COMF TEMPLO, F ; Invert TEMPLO (when in Negative Temperature, the DS18B20 inverts the output so this inverts the register back so its positive) COMF TEMPHI, F ; Invert TEMPHI BCF STATUS, Z ; Clear Zero bit of STATUS register INCF TEMPLO, F ; Increment TEMPLO to add .0625 (after inverting the register, the positive equivelent is .0625 more so this rectifies the negative value being .0625 short) BTFSC STATUS, Z ; Test Z bit of STATUS register to see if last instruction = 0000 0000 INCF TEMPHI, F ; IS 0 (if TEMPLO overflowed to 0, increment TEMPHI once, if not, skip) ; EXAMPLE Negative Temperature AFTER Invert & + 1 TEMPHI = 0000 0001 TEMPLO = 1001 0010 = +25.1250 REARRANGE_NIBBLES ; EXAMPLE, TEMPHI = 0000 0001 TEMPLO = 1001 0010 MOVLW B'11110000' ; W = 1111 0000 ANDWF TEMPLO, W ; F = 1001 0010 W = 1001 0000 IORWF TEMPHI, F ; F = 0000 0001 F = 1001 0001 SWAPF TEMPHI, F ; F = 1001 0001 F = 0001 1001 = New TEMPHI MOVLW B'00001111' ; W = 0000 1111 ANDWF TEMPLO, F ; F = 1001 0010 F = 0000 0010 = New TEMPLO BIN_TO_DEC ; This routine converts an 8-bit number to Decimal and stores the answer in 3 GPR's; HUNS, TENS & ONES ; HUNS holds amount of hundreds (i.e. 0000 0010 = 2x100), TENS holds amount of tens (i.e. 0000 0010 = 2x10) & ONES holds amount of ones (i.e. 0000 0101 = 5x1) INCF TEMPHI ; Preload TEMPHI + 1 CLRF HUNS ; HUNS = 0000 0000 MOVLW D'246' ; MOVE Decimal'246' to W MOVWF TENS ; TENS GPR = 1111 0101 MOVWF ONES ; ONES GPR = 1111 0101 DECFSZ TEMPHI, F ; Decement TEMPHI register GOTO $+D'2' ; NOT 0, skip next instruction GOTO $+D'7' ; IS 0, TEMPHI = 0000 0000, skip next 6 instructions and calculate how many tens and hundreds INCFSZ ONES, F ; Increment ONES register, skip if 0 GOTO $-D'4' ; NOT 0, GOTO here - 4 instructions INCFSZ TENS, F ; IS 0, Increment TENS register skip if 0 GOTO $-D'7' ; GOTO here - 7 instructions & reset the ONES register to D'246' INCF HUNS, F ; TENS overflowed, Increment HUNS GOTO $-D'10' ; GOTO here - 10 instructions & reset the ONES and TENS registers to D'246' SUBWF TENS, F ; W still holds D'246 so subract it from TENS register to determine how many 'TENS' SUBWF ONES, F ; W still holds D'246 so subract it from ONES register to determine how many 'ONES' ; Leading zero suppression & minus (-) sign if Temperature Negative MOVF HUNS, W ; Does HUNS equal 1 or 2? MOVF instruction affects Z bit of STATUS register BTFSC STATUS, Z ; Test Z bit of STATUS register to see if HUNS = 0000 0000 MOVLW B'00001010' ; Jump Pointer for blank arrangement BTFSC FLAGS, 1 ; Is Temperature Negative? MOVLW B'00001011' ; YES, Jump Pointer for - arrangement MOVWF HUNS ; BTFSS STATUS, Z ; Test Z bit of STATUS register to see if HUNS = 0000 0000 GOTO $+D'5' ; HUNS is not, therefore do not blank TENS MOVF TENS, W ; Does TENS equal 0? BTFSC STATUS, Z ; Test Z bit of STATUS register to see if last instruction = 0000 0000 MOVLW B'00001010' ; Jump Pointer for blank arrangement MOVWF TENS ; BCF INTCON, GIE MOVF HUNS, W MOVWF HUNS_ISR MOVF TENS, W MOVWF TENS_ISR MOVF ONES, W MOVWF ONES_ISR BSF INTCON, GIE GOTO GET_TEMP DS18B20_RESET ; This routine Resets the DS18B20 CALL DQ_HIZ CALL DQ_LL ; Force the DQ Line to Logic Low MOVLW (D'480'-5)/5 ; Reset pulse must be held a minimum of 480uS CALL DELAY ; CALL DQ_HIZ ; Release DQ Line MOVLW (D'60'-5)/5 ; Wait for recovery CALL DELAY ; BTFSC PORTA, 4 ; Test for 'Presence Pulse' GOTO DS18B20_RESET ; If not present, Reset MOVLW (D'420'-5)/5 ; Must wait a minmum of 480uS from when DQ line is released before moving on CALL DELAY ; RETURN ; DS18B20_WRITE_BYTE ; This routine writes a byte of data to the DS18B20 MOVWF SHIFT ; MOVE data to shift into DS18B20 to SHIFT GPR MOVLW D'08' ; Amount of bits to shift in MOVWF COUNT ; Store in COUNT GPR RRF SHIFT, F ; Rotate valid data into Carry Flag CALL DS18B20_WRITE_BIT ; Write bit DECFSZ COUNT, F ; Decrement COUNT GOTO $-D'3' ; If not zero, read next bit RETURN ; If zero, RETURN DS18B20_WRITE_BIT ; This routine writes one bit of data to the DS18B20 BCF INTCON, GIE CALL DQ_LL ; Force the DQ Line to Logic Low BTFSS STATUS, C ; Test Carry Flag GOTO $+D'2' ; If zero, leave DQ Line Logic Low CALL DQ_HIZ ; If not zero, release DQ Line to Logic High MOVLW (D'60'-5)/5 ; For delays from 10uS to 1285uS. Example, MOVLW D'10' for 10uS, MOVLW D'500' for 500uS CALL DELAY ; (D'n'-5)/5; n must be divisable by 5 CALL DQ_HIZ ; If not zero, release DQ Line to Logic High BSF INTCON, GIE RETURN DS18B20_READ_BYTE ; This routine reads a byte of data from the DS18B20 MOVLW H'08' ; Amount of bits to shift out MOVWF COUNT ; Store in COUNT GPR CALL DS18B20_READ_BIT ; Read bit RRF SHIFT, F ; Rotate bit out of carry into SHIFT GPR DECFSZ COUNT, F ; Decrement COUNT GOTO $-D'3' ; If not zero, read next bit MOVF SHIFT, W ; If zero, MOVE SHIFT GPR to W RETURN DS18B20_READ_BIT ; This routine reads one bit of data from the DS18B20 BCF INTCON, GIE CALL DQ_LL ; Force the DQ Line to Logic Low CALL DQ_HIZ ; Release DQ Line BSF STATUS, C ; Preset Carry Flag BTFSS PORTA, 4 ; Test DQ Line BCF STATUS, C ; If zero, Clear Carry Flag BSF INTCON, GIE MOVLW (D'60'-5)/5 ; Wait for Time Slot to end CALL DELAY ; RETURN DQ_HIZ ; This routine forces the DQ Line to an Input / High Impedance state BSF PORTA,4 BSF STATUS, RP0 ; Bank 1 BSF TRISA, 4 ; Make Pin 3 an input, Pullup resistor forces line to logic 1, unless DS18B20 pulls it low BCF STATUS, RP0 ; Bank 0 RETURN DQ_LL ; This routine forces the DQ Line to Logic Low BCF PORTA, 4 ; Clear output latch BSF STATUS, RP0 ; Bank 1 BCF TRISA, 4 ; Make Pin 3 an output BCF STATUS, RP0 ; Bank 0 RETURN DELAY ; This routine can provide delays from 10uS to 1285uS depending on the number moved to the Working register prior to calling the delay MOVWF DELAYGPR1 ; Move integer to GPR NOP ; No Operation NOP ; No Operation DECFSZ DELAYGPR1, F ; Decrement GPR and place back in itself GOTO $-D'3' ; Not finished, GOTO here - 3 instructions RETURN ; Finished, Return END