STM32-FPGA_SPI_stm32与fpga的spi通讯

这里是单片机做主机，FPGA做从机

SPI_写（由单片机写入FPGA）

在此之前，先介绍基本的读写函数spi_wr_32bit_MSB_first（B1,B2,B3,B4) 和spi_wr_1bit_cmd_read_16bit()

• 读时序(32位）

void spi_wr_32bit_MSB_first(unsigned char B3,unsigned char B2,unsigned char B1,unsigned char B0){
   
  int i = 0, j = 0;
  unsigned char byte4[4] = {
   0};
  unsigned char buf = 0;
  byte4[3] = B3; byte4[2] = B2; byte4[1] = B1; byte4[0] = B0;

  
  spi_wr_cs(1);
  spi_wr_sck(1);
  spi_wr_sda_out(1);
  // drop down cs
  spi_wr_cs(0);
  Delay(1);
  // drop down sck
  spi_wr_sck(0);
  Delay(1);
  // put data
  for(j = 0; j < 4; j ++){
   
    buf = byte4[3-j];
    for(i = 0; i < 8; i ++){
   
      spi_wr_sda_out(
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