模拟SPI

2万 · 2016-6-11 18:38

有哪位大神帮忙看下69P42模拟SPI的程序有木有问题？
SPI_SENDGET_BYTE:
      PUSH_A
      LDI SPI_COUNT,04H
      ANDIM SPI_FLAG,1101B
SPI_SEND_BYTE1:
      CLR_SCK                               ;拉低时钟信号
      LDA SPI_TMP_H,0
      BA3 SEND_DATA_1                      ;先发送高位
      CLR_SDI
      JMP SPI_SEND_BYTE2
SEND_DATA_1:
      SET_SDI
SPI_SEND_BYTE2:
      NOP
      NOP
      NOP
      SET_SCK
      LDA SPI_TMP_H,0                      ;发送的数据左移
      ADDM SPI_TMP_H,0
      LDA SPI_READBYTE_L,0             ;接收的数据左移
      ADDM SPI_READBYTE_L,0
      LDA PD,0                      ;读取SDO
      BA3 GET_DATA_1
      ANDIM SPI_READBYTE_L,1110B
      JMP SPI_GET_BYTE1
GET_DATA_1:
      ORIM SPI_READBYTE_L,0001B
SPI_GET_BYTE1:
      SBIM SPI_COUNT,01H             ;判断4位是否发送完
      BNZ SPI_SEND_BYTE1
      LDA SPI_FLAG,0
      BA1 SPI_SENDGET_END
      LDI SPI_COUNT,04H
      ORIM SPI_FLAG,0010B             ;4位接收/发送完置位
      LDA SPI_TMP_L,0                      ;把地位赋值给高位
      STA SPI_TMP_H,0
      LDA SPI_READBYTE_L,0             ;先接收的4位数据给高位
      STA SPI_READBYTE_H,0
      JMP SPI_SEND_BYTE1
SPI_SENDGET_END:
      CLR_SCK
      POP_A
      RTNI
有什么问题没有