使用PIC读写1-wire EEPROM DS2430的实例程序

;--------------------------------------------------------------------
;
; 1-wire device access
;DS2430
;memory function
;write scratchpad
;read scratchpad
;
;read memory :
; resource occupy by ICD2
; PROM 0x1f00 - 0x1fff
; RAM 0x70,0xf0,0x170,0x1e5~0x1f0
;--------------------------------------------------------------------
; master action
; 0xf0 + start addr(8) => scratchpad(8) --> master
; none => scratchpad(9) --> master
; none => scartchpad(a) --> master
;
; none => scratchpad(0x1f)--> master[wrap around]
; reset pulse => stop sending data
;
; 0xf0+reset pulse => EEPROM(0x00-0x1F) --> scratchpad(0x00-0x1F)

; copy scratchpad
; master
; 0x55 + 0xa5 => scratchpad(000-0x1f) --> EEPROM(0x00-0x1F)
; held hi for 10ms
; 0xf0 + reset pulse => copy whole from EEPROM to SCRATCHPAD
; use timer as a delay timer
;
; author : Rex Chen
; date : May,8th
; ver : 1.81
;

list p=16F877A
＃i nclude p16f877a.inc
__CONFIG _CPD_OFF _CP_ALL _DEBUG_ON _BODEN_OFF _LVP_OFF _PWRTE_OFF _WDT_OFF _XT_OSC

#define OneWireDHi bsf PORTC,Bit2
#define OneWireDLo bcf PORTC,Bit2

#define CARRY STATUS,C
#define ZERO STATUS,Z

Bit0 equ H'0000'
Bit1 equ H'0001'
Bit2 equ H'0002'
Bit3 equ H'0003'
Bit4 equ H'0004'
Bit5 equ H'0005'
Bit6 equ H'0006'
Bit7 equ H'0007'
;variable defination
cblock 0x20 ; RAM area 0x20- 0x7f
SYSFLAG
TxB ; Command buffer been send
TxBuffer ; data buffer been send
RxB ; Command buffer been received
TempB ; Temp Byte to roll the data
LoopCounter
Addr ; address to access BQ2430A
PBDir ; port C direction log file
PADir ; port A direction log file
Temp
ErrCode ;
W_SAVE
STATUS_SAVE
TxBuf:8 ; Tx Temp buffer
Offset
endc

;;
cblock 0xa0
SARS1
SARS2
SARS3
endc

cblock 0x100
HateSARS1
HateSARS2
HateSARS3
HateSARS4
endc

cblock 0x190
SARSIsAPig0
SARSIsAPig1
SARSIsAPig2
SARSIsAPig3
SARSIsAPig4
SARSIsAPig5
endc

;---------------- SYSFLAG ----------------------------------
fTxHi equ H'0000'
fTxLo equ H'0001'
fRxMode equ H'0002'
;;
;;
;; there are 4 memory block
;; 1. EEPROM 2. memory scratchpad
;; 3. application register
;; 4.register scratchpad
;; aliase
;;
;; memory function
;; write memory scratch
;; read memory scratch
;; copy memory scratch to EEPROM
;; read EEPROM to memory scratch
;;

WScratch equ H'0F' ; 0x0f + Addr + data + data + .+ reset pulse
; // [Master --> ScratchPad ]
RScratch equ H'AA' ; 0xaa + Addr + R + R +.. + reset pulse
; // [ScratchPad --> Master ]
CPScratch equ H'55' ; 0x55 + 0xa5 + hi 10ms // [ScratchPad --> EEPROM ]
REEROM equ H'F0' ; 0xf0 + Addr +R +R + reset pulse
; // [EEPROM(addr) --> ScratchPad]
; 0xf0 + reset pulse // [EEPROM --> ScratchPad]

;; application register , application register is OTP, there are 7 bytes
;; pay attention when you use application register , it's a 64 bit OTP
WApR equ H'99' ; 0x99 + Addr + data + data .. + reset pulse
; [Master --> Application Reg]
RStatus equ H'66' ; 0x66 + 0x00 + status + reset pulse

RApR equ H'C3' ; 0xc3 + addr + data + .. + reset pulse
; application register --> master ( locked)
; register scratchpad --> master ( not lock)
LockAp equ H'5A' ; 0x5A + 0xa5
; [ register scratchpad --> application register]
; 0x5A + reset pulse cancel copy command
; a OTP type do once only

AppLocked equ B'11111100' ; application locked, the value is data in the status

;; ROM function command// implement skip rom only

SkipROM equ H'CC' ;access memory directly
SerachROM equ H'f0' ;read a bit , read the complement of the bit,write bit
MatchROM equ H'55' ;0x55 + 64 bit rom bit
ReadROM equ H'33' ;[family code serial number CRC ==> master ]

org H'00'
nop
goto main

;;ISR **
org H'04'
goto isr
isr
movwf W_SAVE ;; W_SAVE=W
swapf STATUS,W ;;
movwf STATUS_SAVE ;; STATUS_SAVE=STATUS[3:0] STATUS[7:4]
btfss PIR1,TMR1IF ;; TMR1IF
goto exit_int_source_check
;; timer 1 service
nop
nop
nop
nop

exit_int_source_check ;; restore STATUS W before exit from
swapf STATUS_SAVE,W ;; W=STATUS_SAVE=STATUS[3:0] STATUS[7:4]
movwf STATUS
swapf W_SAVE,F ;; restore W
swapf W_SAVE,W
retfie
;; ISR
main

call init
call init_int_en