24c64.asm

这是eeprom24c64的PIC驱动程序。

 LIST p=16f877
 include<p16f877.inc>   
w_temp   equ 0x71
status_temp  equ 0x72
DATA_W   equ  0X75
DATA_R   equ  0X76
DL1      equ  0X77
DL2      equ  0X78
trisc    equ  87h
SCL      EQU  3
SDA      EQU  4
WP       EQU  2
ADDRESS  EQU  0X20
VALUE    EQU  0X55
pclath   equ  0ah 
   org  000h
  nop
  clrf  pclath
  call  init_i2c
  clrf  DATA_R
  movlw VALUE
  movwf DATA_W
  call  WRITE
  call  delay10ms
  call  READ
  goto  $
;------------------------------------
WRITE
writestart
  call    i2c_idle
  banksel SSPCON2
  bsf     SSPCON2,SEN
  banksel PIR1
  btfss   PIR1,SSPIF
  goto    $-1
sendwrtcomm
  movlw   b'10100000'
  banksel SSPBUF
  movwf   SSPBUF
  call    wrtacktest
  
sendaddress
  banksel  SSPSTAT
  btfsc    SSPSTAT,BF
  goto     $-1
  
  movlw    b'00000000'
  banksel  SSPBUF
  movwf    SSPBUF
  call     wrtacktest
  banksel  PIR1
  bcf      PIR1,SSPIF
  
  movlw    ADDRESS
  banksel  SSPBUF
  movwf    SSPBUF
  call     wrtacktest
  
 ; call     delay10ms
senddata
  banksel  SSPSTAT
  btfsc    SSPSTAT,BF
  goto     $-1
  movfw    DATA_W
  banksel  SSPBUF
  movwf    SSPBUF
  call     wrtacktest
  ;call     delay10ms
  banksel  PIR1
  bcf      PIR1,SSPIF
wrtstop
  banksel  SSPCON2
  bsf      SSPCON2,PEN
  banksel  PIR1
  bcf      PIR1,SSPIF
  btfss   PIR1,SSPIF
  goto    $-1
  return
  
;----------------------------------------
READ
reakstart
  call  i2c_idle
  banksel PIR1
  bcf     PIR1,SSPIF
  banksel SSPCON2
  bsf    SSPCON2,RSEN
  banksel PIR1
  btfss  PIR1,SSPIF
  goto   $-1
  
wrtwrite
  movlw  b'10100000'
  banksel SSPBUF
  
  movwf  SSPBUF
  call   wrtacktest
  ;call   delay10ms
wrtaddress
  movlw  B'00000000'
  banksel SSPBUF
  movwf   SSPBUF
  call    wrtacktest
  banksel PIR1
  bcf PIR1,SSPIF
  
  movlw  ADDRESS
  banksel SSPBUF
  movwf   SSPBUF
  call    wrtacktest
  call    delay10ms;
  ;call    delay10ms
restart
  call   i2c_idle
  banksel PIR1
  bcf    PIR1,SSPIF
  banksel SSPCON2  
  bsf     SSPCON2,RSEN
  banksel PIR1
  btfss   PIR1,SSPIF
  goto    $-1
wrtread
  movlw  b'10100001'
  banksel SSPBUF
  movwf   SSPBUF
  call    wrtacktest
 ; call    delay10ms
  banksel PIR1
  bcf     PIR1,SSPIF
startread
  banksel SSPCON2
  bsf     SSPCON2,RCEN
readdata
  banksel PIR1
  bcf     PIR1,SSPIF
  btfss   PIR1,SSPIF
  goto    $-1
  banksel SSPBUF
  movfw   SSPBUF
  movwf   DATA_R
  banksel PIR1
  bcf     PIR1,SSPIF
sendreadnack
  banksel SSPCON2
  bsf     SSPCON2,ACKDT
  bsf     SSPCON2,ACKEN
  banksel PIR1
  btfss   PIR1,SSPIF
  goto    $-1
readstop
  banksel SSPCON2
  bsf     SSPCON2,PEN
  banksel PIR1
  btfss   PIR1,SSPIF
  goto    $-1
  bcf     PIR1,SSPIF
  return

;--------------------------------------

init_i2c
  banksel trisc
  bsf     trisc,SDA
  bsf     trisc,SCL
  banksel SSPADD
  movlw   9
  movwf   SSPADD
  bcf     SSPSTAT,6
  bsf     SSPSTAT,7
  banksel SSPCON
  movlw   b'00111000'
  movwf   SSPCON
  return
;-----------------------------------------
wrtacktest
  banksel  PIR1
  bcf      PIR1,SSPIF
  btfss    PIR1,SSPIF
  goto     $-1
  return
;-----------------------------------------
i2c_idle
  banksel  SSPSTAT
  btfsc    SSPSTAT,R_W
  goto     $-1
  banksel  SSPCON2
  movfw    SSPCON2
  andlw    0x1f
  btfss    STATUS,Z
  goto     $-3
  return
;------------------------------------------
delay10ms
  movlw   d'12'
  movwf   DL1
delay2
  movlw   0xff
  movwf   DL2
delay1
  decfsz  DL2,F
  goto    delay1
  decfsz  DL1,F
  goto    delay2
  return
;----------------------------------------- 
  end