EEPROM.rar_24cxx asm_PIC ASM EEPROM_pic汇编

;此程序适用于PIC单片机读写I2C接口的EEPROM，如24CXX、24LCXX系列的芯片 ;该程序由单片机智能工作室友情提供。 ;***************************************************************** ; 读外部EEPROM子程序 ; ;*******************Initialization subroutine********************* ; This routine initializes the MSSP module ; for I2C Master mode, with a 100 kHz clock. ;***************************************************************** Init bcf status,6 ; Select Bank 01 bsf status,5 movlw b'10011001' movwf trisc ; Set PORTC clrf sspstat ; Disable SMBus inputs bsf sspstat,SMP ; Disable slew rate control movlw 0x18 ; Load 0x18 into WREG movwf sspadd ; Setup 100 kHz I2C clock clrf sspcon2 ; Clear control bits bcf status,5 ; Select Bank 00 movlw b'00101000' movwf sspcon ; Enable SSP, select I2C Master mode bcf pir1,SSPIF ; Clear SSP interrupt flag bcf pir2,BCLIF ; Clear Bit Collision flag retlw 0 ;*******************Start bit subroutine************************** ; This routine generates a Start condition ; (high-to-low transition of SDA while SCL ; is still high. ;***************************************************************** BSTART bcf status,6 bcf status,5 ; Select Bank 00 bcf pir1,SSPIF ; Clear SSP interrupt flag bsf status,5 ; Select Bank 01 bsf sspcon2,SEN ; Generate Start condition bcf status,5 ; Select Bank 00 bstart_wait clrwdt btfss pir1,SSPIF ; Check if operation completed goto bstart_wait ; If not, keep checkin retlw 0 ;*******************Restart bit subroutine************************** ; This routine generates a Repeated Start ; condition (high-to-low transition of SDA ; while SCL is still high. ;***************************************************************** BRESTART bcf status,6 bcf status,5 ; Select Bank 00 bcf pir1,SSPIF ; Clear SSP interrupt flag bsf status,5 ; Select Bank 01 bsf sspcon2,RSEN ; Generate Restart condition bcf status,5 ; Select Bank 00 brestart_wait clrwdt btfss pir1,SSPIF ; Check if operation completed goto brestart_wait ; If not, keep checking retlw 0 ;*******************Stop bit subroutine*************************** ; This routine generates a Stop condition ; (low-to-high transition of SDA while SCL ; is still high. ;***************************************************************** BSTOP bcf status,6 bcf status,5 ; Select Bank 00 bcf pir1,SSPIF ; Clear SSP interrupt flag bsf status,5 ; Select Bank 01 bsf sspcon2,PEN ; Generate Stop condition bcf status,5 ; Select Bank 00 bstop_wait clrwdt btfss pir1,SSPIF ; Check if operation completed goto bstop_wait ; If not, keep checking retlw 0 ;*******************Data transmit subroutine********************** ; This routine transmits the byte of data ; stored in 'datao' to the serial EEPROM ; device. Instructions are also in place ; to check for an ACK bit, if desired. ; Just replace the 'goto' instruction, ; or create an 'ackfailed' label, to provide ; the functionality. ;***************************************************************** TX bcf status,6 bcf status,5 ; Select Bank 00 bcf pir1,SSPIF ; Clear SSP interrupt flag bsf status,5 movf data_out,0 ; Copy datao to WREG bcf status,5 movwf sspbuf ; Write byte out to device tx_wait clrwdt btfss pir1,SSPIF ; Check if operation completed goto tx_wait ; If not, keep checking ; bsf status,5 ; Select Bank 01 ; btfsc sspcon2,ACKSTAT ; Check if ACK bit was received ; goto ackfailed ; This executes if no ACK received retlw 0 ;************************ 数据接受子程序 ********************** ; MCU处接收状态 ; 数据保存在：data_in ;***************************************************************** RX bcf status,6 bcf status,5 ; Select Bank 00 bcf pir1,SSPIF ; Clear SSP interrupt flag bsf status,5 ; Select Bank 01 bsf sspcon2,RCEN ; Initiate reception of byte bcf status,5 ; Select Bank 00 rx_wait clrwdt btfss pir1,SSPIF ; Check if operation completed goto rx_wait ; If not, keep checking movf sspbuf,0 ; Copy byte to WREG bsf status,5 movwf data_in ; Copy WREG to data_in bcf status,5 bcf pir1,SSPIF ; Clear SSP interrupt flag bsf status,5 ; Select Bank 01 bsf sspcon2,ACKEN ; Generate ACK/NO ACK bit bcf status,5 ; Select Bank 00 rx_wait2 clrwdt btfss pir1,SSPIF ; Check if operation completed goto rx_wait2 ; If not, keep checking retlw 0 ;************************写一个字节子程序************************* ; 输入：被写的数据存在eebuff中 ; 数据存放的地址在eeaddr_h\eeaddr_l中 ; 写芯片控制字保存在control_ee中 ;***************************************************************** ByteWrite call BSTART ; Generate Start condition bsf status,5 ; Send control byte movf control_ee,0 ; Load control byte for write movwf data_out ; Copy to datao for output call TX ; Send control byte to device ; Send word address high byte bsf status,5 ; Select Bank 00 movf eeaddr_h,0 ; Load the msb for word address movwf data_out ; Copy to datao for output call TX ; Send word address low byte bsf status,5 ; Select Bank 00 movf eeaddr_l,0 ; Load the lsb for word address movwf data_out ; Copy to datao for output call TX ; Send word address to device ; Send data byte bsf status,5 ; Select Bank 00 movf eebuff,0 ; Load data byte movwf data_out ; Copy to datao for output call TX ; Send data byte to device call BSTOP ; Generate Stop condition call Poll ; Poll for write completion return ;******************* 写一页数据到EEPROM ************************ ; ;输入：连续写的字节数保存在count_ee中 ; 数据写到EEPROM中的起始地址保存在eeaddr_h\eeaddr_l中 ; 被写的数据保存在以wrbuff为首的数据缓冲器中 ; 写芯片控制字保存在control_ee中 ;***************************************************************** PageWrite call BSTART ; Generate start bit bsf status,5 ; Now we send the control byte