INCLUDE    "P16C716.EQU"
;RAM通用寄存器定义


LP1             EQU        29H      ;循环次数计数器1(用于DS1302)
LP2             EQU        2AH      ;循环次数计数器2(也用于X25045)

BUFF            EQU        2CH

COUNT           EQU        2DH      ;计数变化量(用于X25045)
COUNTBUF        EQU        2EH      ;计数变化量缓存器
WRXBUF          EQU        2FH      ;存储写入数据缓存器
RDXBUF          EQU        30H    
ADDRESS1        EQU        31H      ;写地址暂存器
ADDRESS2        EQU        32H      ;读地址暂存器
   
ADDH            EQU        50H      ;第八位地址保护(用于X25045)
RXDATA          EQU        6AH      ;存储读出数据(2 OR 3 BYTE)[51H--53H]
WXDATA          EQU        6BH      ;存储写入数据(2 OR 3 BYTE)[54H--56H]




;标志和标志位定义

SI              EQU          1      ;A口位定义(X25045)
CS              EQU          2
SO              EQU          3
SCK             EQU          4

INIT
    BSF         STATUS,RP0   
    MOVLW       0X08
    MOVWF       TRISA              ;RA3 input
    BCF         STATUS,RP0
    CLRF        ADCON0             ;禁止AD转换
   

    BSF         PORTA,CS
    BSF         PORTA,SO
    BCF         PORTA,SI
    BCF         PORTA,SCK

    CALL        WREN_CMD
    CALL        WRSR_CMD
    CALL        WREN_CMD

    CLRF        WRXBUF
    BCF         STATUS,C
    CALL        BYTE_WRITEX
    CLRF        WRXBUF
    BCF         STATUS,C
    CALL        BYTE_READX
                                   

    CALL        RST_DOG
    
    GOTO        OVER
WREN_CMD                            ;WRITE ENABLE SUBPROGRAM
    BSF         PORTA,CS
    NOP
    BCF         PORTA,SCK
    NOP
    BCF         PORTA,CS
    MOVLW       0X06
    MOVWF       WRXBUF              ;WRITE  WREN
    CALL        WRBX
    BCF         PORTA,SCK
    BSF         PORTA,CS
    NOP
    NOP
    RETURN
WRSR_CMD                            ;WRITE STATUS
    BSF         PORTA,CS
    NOP
    BCF         PORTA,SCK
    NOP
    BCF         PORTA,CS
    MOVLW       0X01
    MOVWF       WRXBUF              ;WRITE  WRSR
    CALL        WRBX
    MOVLW       0X00                ;无块保护
    MOVWF       WRXBUF              ;看门狗超时周期1.4s
    CALL        WRBX
    BCF         PORTA,SCK
    BSF         PORTA,CS
    NOP
    NOP
    CALL        WIP_CHK
    RETURN
RDSR_CMD                            ;READ  STATUS
    BSF         PORTA,CS
    NOP
    BCF         PORTA,SCK
    NOP
    BCF         PORTA,CS
    MOVLW       0X05
    MOVWF       WRXBUF              
    CALL        WRBX
    CALL        RDBX
    BCF         PORTA,SCK
    BSF         PORTA,CS
    NOP
    NOP
    RETURN
BYTE_WRITEX                         ;WRITE 1 BYTE INTO X25045
    BSF         PORTA,CS
    NOP
    BCF         PORTA,SCK
    NOP
    BCF         PORTA,CS
    RLF         WRXBUF
    RLF         WRXBUF
    RLF         WRXBUF
    RLF         WRXBUF  
    MOVLW       0X02
    IORWF       WRXBUF              ;SEND HIGH ADDRESS
    CALL        WRBX
    MOVLW       0X55
    MOVWF       WRXBUF
    CALL        WRBX                ;SEND LOW 8 ADDRESS 55H
    MOVLW       0X05                ;SEND DATA
    MOVWF       WRXBUF
    CALL        WRBX 
    BCF         PORTA,SCK
    BSF         PORTA,CS
    NOP
    NOP
    CALL        WIP_CHK
    RETURN
BYTE_READX                          ;READ 1 BYTE FROM  E2PROM ,ADDRESS2=A0~A7, C=A8
    BSF         PORTA,CS
    NOP
    BCF         PORTA,SCK
    NOP
    BCF         PORTA,CS
    RLF         WRXBUF
    RLF         WRXBUF
    RLF         WRXBUF
    RLF         WRXBUF              ;SEND HIGH ADDRESS
    MOVLW       0X03
    IORWF       WRXBUF
    CALL        WRBX
    MOVLW       0X55
    MOVWF       WRXBUF
    CALL        WRBX                ;SEND LOW 8 ADDRESS
    CALL        RDBX
    MOVF        RDXBUF,0
    MOVWF       RXDATA
    BCF         PORTA,SCK
    BSF         PORTA,CS
    NOP
    NOP
    RETURN
    
WRBX                                ;WRITE 1 BYTE FROM WRXBUF TO X25045 
    NOP
    MOVLW       0X08
    MOVWF       LP1
WRBX1
    BCF         PORTA,SCK
    BTFSS       WRXBUF,7
    BCF         PORTA,SI
    BTFSC       WRXBUF,7
    BSF         PORTA,SI
    BSF         PORTA,SCK
    RLF         WRXBUF,1
    DECFSZ      LP1,1
    GOTO        WRBX1
    RETURN
RDBX                                ;READ 1 BYTE FROM X25045 TO RDXBUF
    MOVLW       0X08
    MOVWF       LP2
RDBX1
    BSF         PORTA,SCK
    NOP
    BCF         STATUS,C
    BCF         PORTA,SCK
    BTFSC       PORTA,SO
    BSF         STATUS,C
    RLF         RDXBUF,1
    DECFSZ      LP2,1
    GOTO        RDBX1          
    RETURN
WIP_CHK                            ;等待X25045结束内部写周期
    MOVLW       0X99
    MOVWF       TIMER
WIP_CHK1 
    CALL        RDSR_CMD 
    BTFSC       RDXBUF,0
    GOTO        WIP_CHK2
    GOTO        WIP_CHK3
WIP_CHK2
    DECFSZ      TIMER,1
    GOTO        WIP_CHK1
WIP_CHK3
    RETURN  
RST_DOG                            ;复位看门狗定时器子程序
    BCF         PORTA,CS
    BSF         PORTA,CS
    RETURN


OVER
    END