exp12.asm

ADuc812的各种功能程序的例子!很有参考价值

                                                            ; RCVDATA
;向器件指定子地址读取N个数据
;入口参数:  器件从地址SLAVEADD、器件子地址SUBADD、接收字节数NUMBYTE
;出口参数:  接收数据缓冲区RDBUFF
;占用：A、 R1、 R3、 CY               

; receives one or more bytes of data from an I2C slave device.

RCVDATA:  
	nop
	nop
	PUSH    01H
        PUSH    03H 
        PUSH    ACC
        MOV     R3,NUMBYTE 	
	
        ; send start bit
        LCALL   STARTBIT        ; acquire bus and send slave address

        ; send slave address
        MOV     A, SLAVEADD
        LCALL   SENDBYTE        ; sets NOACK if NACK received
        JB      NOACK, STOPRCV	; if no acknowledge send stop

	; send subaddress
	MOV     A,SUBADD
	LCALL   SENDBYTE
        JB      NOACK, STOPRCV	; if no acknowledge send stop

        ; send start bit
        LCALL   STARTBIT        ; acquire bus and send slave address

        ; send slave address
	INC     SLAVEADD       	; Set RW for reception
        MOV     A, SLAVEADD
        LCALL   SENDBYTE        ; sets NOACK if NACK received
        JB      NOACK, STOPRCV  ; Check for slave not responding.
	LCALL	DELAY		; this lets slave get data ready 

	MOV     R1, #RDBUFF
RERDN:  
	nop
	nop
	LCALL   RCVBYTE         ; Receive next data byte.
        MOV     @R1, A        	; Save data byte in buffer.
        DJNZ    R3, TACK           
        CALL    RCVNACK         ;最后一字节发非应答位 
STOPRCV: 
	nop
	nop     
        LCALL   STOPBIT
        JNB     NOACK, RCVRET   ; if slave sends NACK send error
        SETB    ERR             ; sets the error flag
        SETB    I2CRS           ; this resets the I2C interface
	
RCVRET:	
	NOP
	NOP
	POP     ACC
        POP     03H
        POP     01H
        RET
TACK:   
	nop
	nop
	LCALL   RCVACK		;发应答位
	INC     R1
	SJMP    RERDN
	RET

;____________________________________________________________________
;                                                              
;启动I2C总线子程序
;____________________________________________________________________
                                                              ; delay

Delay:	  PUSH 07H
	  MOV R7,#5H
	  DJNZ R7,$
	  POP 07H
	  RET
;____________________________________________________________________
                                                              ; ERROR
; this subroutine is run if a NACK is recieved from the slave

ERROR:
	LCALL	DSPERR	; display the error letter E 
	RET

;____________________________________________________________________
                                                           ; STARTBIT
; Sends the start bit to initiate an I2C communication

STARTBIT:
	NOP
	CLR     NOACK
	SETB    MDE             ; enable SDATA pin as an output
	NOP
	NOP
	NOP
	NOP
	SETB    MDO
	NOP
	NOP
	NOP
	NOP
	SETB    MCO
	NOP
	NOP
	NOP
	NOP
        CLR     MDO             ; low O/P on SDATA 
        LCALL   DELAY           ; delay 5 Machine cycles
        CLR     MCO             ; start bit
        RET

;____________________________________________________________________
                                                            ; STOPBIT
; Sends the stop bit to end an I2C transmission

STOPBIT:

        SETB    MDE             ; to enable SDATA pin as an output
	NOP
	NOP
	NOP
	NOP
        CLR     MDO             ; get SDATA ready for stop
	NOP
	NOP
	NOP
	NOP
        SETB    MCO             ; set clock for stop
        LCALL   DELAY
        SETB    MDO             ; this is the stop bit
        RET
;____________________________________________________________________
                                                            ; RCVACK
;发送应答信号子程序

RCVACK:
 	SETB    MDE             ; Data pin of the master must be an..
        NOP
	NOP
	NOP
	NOP	
        CLR     MDO             ; Send no acknowledge, last byte.
       	NOP
	NOP
	NOP
	NOP
	SETB    MCO             ; Send no-acknowledge clock.
        LCALL   DELAY
        CLR     MCO		; clear clock
        RET

;____________________________________________________________________
                                                            ; RCVNACK
;发送非应答信号

RCVNACK:
 	SETB    MDE             ; Data pin of the master must be an..
                                ; ..output for the acknowledge	
	NOP
	NOP
	NOP
	NOP
        SETB    MDO             ; Send no acknowledge, last byte.
       	NOP
	NOP
	NOP
	NOP
	SETB    MCO             ; Send no-acknowledge clock.
        LCALL   DELAY
        CLR     MCO		; clear clock
        RET

;____________________________________________________________________
                                                           ; SENDBYTE
; Send 8-bits in ACC to the slave

SENDBYTE:

        MOV     BITCNT,#8       ; 8 bits in a byte
        SETB    MDE             ; to enable SDATA pin as an output	
        CLR     MCO             ; make sure that the clock line is low
SENDBIT:
	RLC     A               ; put data bit to be sent into carry
        MOV     MDO,C           ; put data bit on SDATA line
        SETB    MCO             ; clock to send bit
        LCALL   DELAY
        CLR     MCO             ; clear clock 
        DJNZ    BITCNT,SENDBIT	; jump back and send all eight bits

        CLR     MDE             ; release data line for acknowledge
        SETB    MCO             ; send clock for acknowledge
	LCALL   DELAY
        JNB     MDI,NEXT        ; this is a check for acknowledge
        SETB    NOACK           ; no acknowledge, set flag		
NEXT:   CLR     MCO             ; clear clock 
	RET


;____________________________________________________________________
                                                  ; RCVBYTE
; receives one byte of data in ACC from an I2C slave device.

RCVBYTE:
        MOV     BITCNT,#8       ; Set bit count.
        CLR     MDE             ; to enable SDATA pin as an input
	nop
	nop	
        CLR     MCO		; make sure the clock line is low
	nop
	nop
	
RCVBIT:  
	SETB    MCO		; clock to recieve bit
	nop
	nop	
        CLR     MCO		; clear clock
	NOP
	NOP
        MOV     C,MDI           ; read data bit into carry.
        RLC     A               ; Rotate bit into result byte.
	
        DJNZ    BITCNT,RCVBIT   ; Repeat until all bits received.
				; recieved byte is in the accumulator

        RET

;____________________________________________________________________
						;DISPLAY 

DSPDATA: 
	 PUSH	00H
	 PUSH   01H
	 PUSH   02H
	 PUSH   ACC
	 MOV R0,#RDBUFF
         MOV R1,#DSPBUFF
;         MOV R2,#03H
CHA:     MOV A,@R0
         ANL A,#0FH
	 MOV @R1,A
	 INC R1
         MOV A,@R0
         SWAP A
         ANL A,#07H
	 MOV @R1,A
         INC R0
         INC R1 ;seconds 

         MOV A,@R0
         ANL A,#0FH
	 MOV @R1,A
	 INC R1
         MOV A,@R0
         SWAP A
         ANL A,#07H
	 MOV @R1,A
         INC R0
         INC R1  ;minutes

         MOV A,@R0
         ANL A,#0FH
	 MOV @R1,A
	 INC R1
         MOV A,@R0
         SWAP A
         ANL A,#03H
	 MOV @R1,A
         INC R0
         INC R1  ;hours

;         DJNZ R2, CHA
	 MOV @R1,#0FFH
	 POP	ACC
	 POP	02H
	 POP	01H
	 POP	00H
         RET

	
;入口：@R0显示数据	
DISP_data:
	NOP
	MOV A,@R0 
	MOV DPTR,#TAB
	MOVC A,@A+DPTR
	MOV DPP,#io_page
	MOV DPTR,#led8seg_port
	MOVX @DPTR,A
	ret
	
;入口：R1显示位置		
disp_bit:
	NOP
	MOV A,R1
	MOV DPP,#io_page
	MOV DPTR,#led8bit_port
	MOVX @DPTR,A
	RET

TAB:    DB 0C0H,0F9H,0A4H,0B0H,99H,92H,82H,0F8H,80H,90H,88H,83H,0C6H,0A1H,86H,8EH;0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F


DELAY_1MS:
	nop
	MOV	R6,#250
DELAY_1MS1:
	NOP
	NOP
	DJNZ	R6,DELAY_1MS1
	RET
;____________________________________________________________________
END