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Manu013
J'avais fait un post sur abc a ce sujet, mais (...)
j'ai retrouvé les dites routines dans une app note de maxim ( http://pdfserv.maxim-ic.com/en/an/AN2420.pdf ) :
Citation:
; *******************************************************
;
; Dallas 1-Wire Support for PIC16F628
;
; Processor has 4MHz clock and 1µs per instruction cycle.
;
; *******************************************************
; *******************************************************
; Dallas Semiconductor 1-Wire MACROS
; *******************************************************
OW_HIZ:MACRO
BSF STATUS,RP0 ; Select Bank 1 of data memory
BSF TRISB, DQ ; Make DQ pin High Z
BCF STATUS,RP0 ; Select Bank 0 of data memory
ENDM
; --------------------------------------------------------
OW_LO:MACRO
BCF STATUS,RP0 ; Select Bank 0 of data memory
BCF PORTB, DQ ; Clear the DQ bit
BSF STATUS,RP0 ; Select Bank 1 of data memory
BCF TRISB, DQ ; Make DQ pin an output
BCF STATUS,RP0 ; Select Bank 0 of data memory
ENDM
; --------------------------------------------------------
WAIT:MACRO TIME
;Delay for TIME µs.
;Variable time must be in multiples of 5µs.
MOVLW (TIME/5)-1 ;1µs
MOVWF TMP0 ;1µs
CALL WAIT5U ;2µs
ENDM
; *******************************************************
; Dallas Semiconductor 1-Wire ROUTINES
; *******************************************************
WAIT5U:
;This takes 5uS to complete
NOP ;1µs
NOP ;1µs
DECFSZ TMP0,F ;1µs or 2µs
GOTO WAIT5U ;2µs
RETLW 0 ;2µs
; --------------------------------------------------------
OW_RESET:
OW_HIZ ; Start with the line high
CLRF PDBYTE ; Clear the PD byte
OW_LO
WAIT .500 ; Drive Low for 500µs
OW_HIZ
WAIT .70 ; Release line and wait 70µs for PD Pulse
BTFSS PORTB,DQ ; Read for a PD Pulse
INCF PDBYTE,F ; Set PDBYTE to 1 if get a PD Pulse
WAIT .400 ; Wait 400µs after PD Pulse
RETLW 0
; --------------------------------------------------------
DSRXBYTE: ; Byte read is stored in IOBYTE
MOVLW .8
MOVWF COUNT ; Set COUNT equal to 8 to count the bits
DSRXLP:
OW_LO
NOP
NOP
NOP
NOP
NOP
NOP ; Bring DQ low for 6µs
OW_HIZ
NOP
NOP
NOP
NOP ; Change to HiZ and Wait 4µs
MOVF PORTB,W ; Read DQ
ANDLW 1<<DQ ; Mask off the DQ bit
ADDLW .255 ; C=1 if DQ=1: C=0 if DQ=0
RRF IOBYTE,F ; Shift C into IOBYTE
WAIT .50 ; Wait 50µs to end of time slot
DECFSZ COUNT,F ; Decrement the bit counter
GOTO DSRXLP
RETLW 0
; --------------------------------------------------------
DSTXBYTE: ; Byte to send starts in W
MOVWF IOBYTE ; We send it from IOBYTE
MOVLW .8
MOVWF COUNT ; Set COUNT equal to 8 to count the bits
DSTXLP:
OW_LO
NOP
NOP
NOP ; Drive the line low for 3us
RRF IOBYTE,F
BSF STATUS,RP0 ; Select Bank 1 of data memory
BTFSC STATUS,C ; Check the LSB of IOBYTE for 1 or 0
BSF TRISB,DQ ; HiZ the line if LSB is 1
BCF STATUS,RP0 ; Select Bank 0 of data memory
WAIT .60 ; Continue driving line for 60µs
OW_HIZ ; Release the line for pullup
NOP
NOP ; Recovery time of 2µs
DECFSZ COUNT,F ; Decrement the bit counter
GOTO DSTXLP
RETLW 0
; --------------------------------------------------------
Appendix B: PIC16F628 to DS2761 Assembly Code (PIC_2_1W.ASM)
; *******************************************
;
; Dallas Semiconductor PIC code
;
; This code will interface a PIC16F628 microcontroller to
; a DS2761 High-Precision Li+ Battery Monitor
;
; *******************************************;
;
; VCC
; ^
; |
; |
; /
; \ Rpup
; /
; \
; |
; 16F628 | DS2761
; RB1 (pin 7) ------------------------------ DQ (pin 7)
;
; *******************************************;
;---------------------------------------------------------
; List your processor here.
list p=16F628
; Include the processor header file here.
#include <p16F628.inc>
;---------------------------------------------------------
; Assign the PORTB with Constants
constant DQ=1 ; Use RB1 (pin7) for 1-Wire
;--------------------------------------------------------
; These constants are standard 1-Wire ROM commands
constant SRCHROM=0xF0
constant RDROM=0x33
constant MTCHROM=0x55
constant SKPROM=0xCC
;---------------------------------------------------------
; These constants are used throughout the code
cblock 0x20
IOBYTE
TMP0 ; Address 0x23
COUNT ; Keep track of bits
PICMSB ; Store the MSB
PICLSB ; Store the LSB
PDBYTE ; Presence Detect Pulse
endc
;---------------------------------------------------------
; Setup your configuration word by using __config.
; For the 16F628, the bits are:
; CP1,CP0,CP1,CP0,N/A, CPD, LVP, BODEN, MCLRE, FOSC2, PWRTE, WDTE, FOSC1, FOSC0
; CP1 and CP0 are the Code Protection bits
; CPD: is the Data Code Protection Bit
; LVP is the Low Voltage Programming Enable bit
; PWRTE is the power-up Timer enable bit
; WDTE is the Watchdog timer enable bit
; FOSC2, FOSC1 and FOSC0 are the oscillator selection bits.
; CP disabled, LVP disabled, BOD disabled, MCLR enabled, PWRT disabled, WDT disabled, INTRC I/O oscillator
; 11111100111000
__config 0x3F38
;---------------------------------------------------------
; Set the program origin for subsequent code.
org 0x00
GOTO SETUP
NOP
NOP
NOP
GOTO INTERRUPT ; PC 0x04...INTERRUPT VECTOR!
;---------------------------------------------------------
INTERRUPT:
SLEEP
;---------------------------------------------------------
; Option Register bits
; ____
; RBPU,INTEDG,TOCS,TOSE,PSA,PS2,PS1,PS0
; 7=PORTB Pullup Enable, 6=Interrupt Edge Select, 5=TMR0 Source,
; 4=TMR0 Source Edge, 3=Prescaler Assign, 2-0=Prescaler Rate Select
; 11010111
; PORTB pullups disabled,rising edge,internal,hightolow,TMR0,1:256
SETUP:
BCF STATUS,RP1
BSF STATUS,RP0 ; Select Bank 1 of data memory
MOVLW 0xD7
MOVWF OPTION_REG
BCF STATUS,RP0 ; Select Bank 0 of data memory
;---------------------------------------------------------
BCF INTCON,7 ; Disable all interrupts.
;---------------------------------------------------------
GOTO START
;---------------------------------------------------------
; Include the 1-Wire communication routines and macros
#INCLUDE 1w_16f6x.inc
;---------------------------------------------------------
START:
;---------------------------------------------------------
GET_TEMP:
CALL OW_RESET ; Send Reset Pulse and read for Presence Detect Pulse
BTFSS PDBYTE,0 ; 1 = Presence Detect Detected
GOTO NOPDPULSE
MOVLW SKPROM
CALL DSTXBYTE ; Send Skip ROM Command (0xCC)
MOVLW 0x69
CALL DSTXBYTE ; Send Read Data Command (0x69)
MOVLW 0x0E
CALL DSTXBYTE ; Send the DS2761 Current Register MSB address (0x0E)
CALL DSRXBYTE ; Read the DS2761 Current Register MSB
MOVF IOBYTE,W
MOVWF PICMSB ; Put the Current MSB into file PICMSB
CALL DSRXBYTE ; Read the DS2761 Current Register LSB
MOVF IOBYTE,W
MOVWF PICLSB ; Put the Current LSB into file PICLSB
CALL OW_RESET
NOPDPULSE: ; Add some error processing here!
SLEEP ; Put PIC to sleep
;---------------------------------------------------------
end
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