SPI mode 程序求助

只看该作者 · 2007-9-13 11:59

这是一个我写的SPI mode0的程序
6502内核.
可是发送完后得到的数据不对,那位能帮我看看嘛,谢谢
SPI_RW:.proc
    PHA
    TXA
    PHA
    TYA
    PHA
    .if 1
    LDX #0
    LDY #0
SPI_LOOP#:
    %SetSCLK
    tya
    asl    a
    tay
    lda 08h
    and #SPI_DO
    beq _RE#
    tya
    ora #0x01
    tay
_RE#:
    lda _SPI_Data
    and #0x80
    beq Bit_Zero
    %SetSI
    jmp SI_Over
Bit_Zero:
    %ClrSI
SI_Over:
    asl _SPI_Data
    %ClrSCLK
    inx
    txa
    cmp #0x08
    bmi SPI_LOOP#
    tya
    sta _SPI_Data
          rts
.endp

只看该作者 · 2007-9-13 12:19

程序已修改成这样
lda _SPI_Data
    and #0x80
    beq Bit_Zero
    %SetSI
    jmp SI_Over
Bit_Zero:
    %ClrSI
SI_Over:
    asl _SPI_Data
    %SetSCLK
    tya
    asl    a
    tay
    lda 08h
    and #SPI_DO
    beq _RE#
    tya
    ora #0x01
    tay
_RE#:
    %ClrSCLK
    inx
    txa
    cmp #0x08
    bmi SPI_LOOP#
    tya
    sta _SPI_Data
    .else
        lda _SPI_Data
        sta P_3003H_SPI_TXD3
        lda #%10000000
        sta P_3008H_SPICTL0
SPI_Ready:
        lda P_3009H_SPICTL1
        and #0x01
        beq SPI_Ready
        lda P_3007H_SPI_RXD3
        sta _SPI_Data