讀寫24LCxx系列的EEPROM的實例程序
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;*
;*******************************************************
;
; Send Command for BYTE WRITE :
; Start+ 0xA0 + EE_Address + Write_Data + Stop
;
EE_Byte_Write
call StartI2C ; Set SSPCON2.SEN
;
bcf I2C_Ctrl,0 ; Clear for Write Command
movf I2C_Ctrl,W ; Send Slave Address to I2C Bus
call Send_Byte
;
movf I2C_Addr,W ; Send out the Command
call Send_Byte
;
movf I2C_Data,W ; Send out the Data
call Send_Byte
;
call StopI2C ; Initial STOP Condition
return
;
;**********************************************************************
;
; As following subroutines perform commonly used I2C functions.
; You can use these subroutines for your I2C access
;
;**********************************************************************
;
;*** Initial I2Cmodule fot 7-bit I2C Master Mode with 100Kcps @4MHz
;
Init_I2C_Master
BANKSEL TRISC ; Initial PortC,bit 3 4 as Input
bsf SCL ; RC3 = SCL , RC4 = SDA
bsf SDA
;
BANKSEL PORTC
bsf SCL ; SCL = Hi
bsf SDA ; SDA = Hi
;
movlw b'00101000' ; I2C Master Mode, Clock Rate: FOSC/(4*SSPADD+1)
movwf SSPCON ;
;
banksel SSPADD
movlw .9 ; This gives 100KHz I2C clock @ 4MHz
movwf SSPADD ; (4MHz/4) / (9+1)= 100KHz
;
movlw b'10000000' ; Disable slew rate control,
movwf SSPSTAT ; and clear status bits
;
movlw b'00000000' ; Set SCL,SDA into Ready status
movwf SSPCON2
;
return
;
;****** Send START condition to bus *******
;
StartI2C ; Initiate the I2C START condition.
banksel SSPCON2
bsf SSPCON2,SEN
goto I2C_Done
;
;****** Send STOP condition to bus *******
;
StopI2C
banksel SSPCON2
bsf SSPCON2,PEN
goto I2C_Done
;
;****** Send RESTART condition to bus *******
;
RstartI2C
banksel SSPCON2
bsf SSPCON2,RSEN
goto I2C_Done
;
;****** Send a Non-Acknowledge status to bus (ACK=1) *******
;
Non_Ack
banksel SSPCON2
bsf SSPCON2,ACKDT ; Set the ACK bit
bsf SSPCON2,ACKEN ; Initiate the NACK sequence.
goto I2C_Done
;
;****** Send an Acknowledge status to bus (ACK=0) *******
;
An_Ack
banksel SSPCON2
bcf SSPCON2,ACKDT ; Clear the ACK bit
bsf SSPCON2,ACKEN ; Initiate the NACK sequence.
goto I2C_Done
;
;****** Send data to I2C bus from Wreg. *******
;
Send_Byte
banksel SSPBUF
movwf SSPBUF
goto I2C_Done
;
;****** Enable I2C Receive for Master Mode *******
;
RecI2C
banksel SSPCON2
bsf SSPCON2,RCEN ; Set the receive enable bit.
goto I2C_Done
;
;****** Check the I2C stage is completed ********
;
I2C_Done
banksel PIR1
btfss PIR1,SSPIF ; Poll for SSPIF
goto $-1
bcf PIR1,SSPIF
return
;
Delay_mS
banksel D_Count
movlw .124 ; Load .5mS Dealy Value
movwf D_Count
_D_mS nop
decfsz D_Count,F
goto _D_mS
return
;
; *********** End Of Program !!!!!
;
end本文引用地址：http://www.104case.com/article/172784.htm
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