LIST P=PIC16F628A INCLUDE P16F628A.INC __CONFIG (0x3F38); CBLOCK H'20' HUNS ; BCD number pointer for HUNDREDS digit TENS ; BCD number pointer for TENS digit ONES ; BCD number pointer for ONES digit TENTHS ; BCD number pointer for TENTHS digit HUNS_ISR ; BCD number pointer for HUNDREDS digit, used within ISR TENS_ISR ; BCD number pointer for TENS digit, used within ISR ONES_ISR ; BCD number pointer for ONES digit, used within ISR TENTHS_ISR ; BCD number pointer for TENTHS digit, used within ISR TEMPLO ; BS18B20 Temperature Result Low Byte TEMPHI ; BS18B20 Temperature Result High Byte COUNT ; For counting execution times in various routines SHIFT ; For storing data to shift into and out of the DS18B20 COLSEL ; Stores Column Select information DIGIT ; Used for Indirect Addressing in Interrupt DELAYGPR1 ; Used in delay subroutines FLAGS ; -------0 Unused INDEX ; ------1- Temperature Negative Flag (1 = True 0 = False) COLUMN ; -----0-- Unused ; ----0--- Unused ; ---0---- Unused ; --0----- Unused ; -0------ Unused ; 0------- Unused ENDC W_ISR EQU H'70' ; For context saving. Ensures GPR is accesible from any Bank. See Memory Map of 628A S_ISR EQU H'71' ; For context saving. Ensures GPR is accesible from any Bank. See Memory Map of 628A P_ISR EQU H'72' ; For context saving. Ensures GPR is accesible from any Bank. See Memory Map of 628A F_ISR EQU H'73' ; For context saving. Ensures GPR is accesible from any Bank. See Memory Map of 628A ORG H'000' ; Processor reset vector location. On power up, the program jumps here GOTO SETUP ; ;-------------------------------------------------------------------------------------------------------------- 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 MOVLW B'00010000' ; RA<7:5><3:0> Output, RA<4> Input MOVWF TRISA ; CLRF TRISB ; RB<7:0> Outputs BCF STATUS, RP0 ; Bank 0 CLRF PORTA CLRF PORTB MOVLW .12 MOVWF COLUMN CLRF DIGIT CLRF INDEX GOTO GET_TEMP ; Dallas DS18B20 Temperature Sensor 'One Wire' Communication Routines DS18B20_RESET ; This routine Resets the DS18B20 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_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 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 MOVLW (D'60'-5)/5 ; Wait for Time Slot to end 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 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 RETURN ; DQ_HIZ ; This routine forces the DQ Line to an Input / High Impedance state 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 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 ;------------------------------------------------------------------------------------------------------------------- GET_TEMP CALL DS18B20_RESET ; 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' ; Transmitting 0 therefore NOT done 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 DISPLAY BSF PORTA,0 BSF PORTA,1 BSF PORTA,2 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 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 GOTO DISPLAY ;-------------------------------------------------------------------------------------- END