软件模拟spi c语言实现

//spi数据写入驱动
void SPI_SEND_BYTE(uint8_t data)
{
    uint8_t i = 0;
    uint8_t tmp = data;
    for (i = 0; i < 8; i++)
    {
        SIMU_SPI_SCK_L();
        sleep_us(1);
        if (tmp & 0x80)
        {
            SIMU_SPI_SDA_H();
        }
        else
        {
            SIMU_SPI_SDA_L();
        }
        sleep_us(1);
        SIMU_SPI_SCK_H();
        sleep_us(1);
        tmp <<= 1;
        sleep_us(1);
    }
}

//spi数据读取驱动
uint16_t SPI_RECV_BYTE(void)
{
    uint16_t data = 0;
    uint8_t i = 0;

    SIMU_SPI_SDA_INPUT();
    SIMU_SPI_SCK_L();
    for (i = 0; i < 16; i++)
    {
        sleep_us(1);
        data <<= 1;
        sleep_us(1);
        SIMU_SPI_SCK_H();
        sleep_us(1);
        if (IS_SIMU_SPI_SDA_H())
        {
            data |= 0x01;
        }
        sleep_us(1);
        SIMU_SPI_SCK_L();
    }
    SIMU_SPI_SDA_OUTPUT();
    return data;
}

//写寄存器数据
void WriteReg_shell(uint8_t addr, uint16_t word)
{
    SIMU_SPI_SDA_OUTPUT();
    SIMU_SPI_SCK_L();
    SPI_NSS_ACTIVE();
  
    uint16_t temp = word >> 8;
    SPI_SEND_BYTE(addr);
    SPI_SEND_BYTE((temp)&0xFF);
    SPI_SEND_BYTE((word)&0xFF);
    SPI_NSS_INACTIVE();
}

//读寄存器数据
uint16_t ReadReg_shell(uint8_t addr)
{
    uint16_t word;
    SIMU_SPI_SDA_OUTPUT();
    SIMU_SPI_SCK_L();
    SPI_NSS_ACTIVE();
  
    uint8_t tmp_addr = (addr | 0x80);
    SPI_SEND_BYTE(tmp_addr);
    sleep_us(2);
    word = SPI_RECV_BYTE();
    SPI_NSS_INACTIVE();

    return word;
}

代码说明：
前面两个函数是读取/写入的时序
后面两个函数是读取设备寄存器的demo代码


其中需要注册进去的接口

一、设置spi clk引脚高低

SIMU_SPI_SCK_H(); 

SIMU_SPI_SCK_L();

二、设置spi data引脚高低

SIMU_SPI_SDA_H();

SIMU_SPI_SDA_L();

三、设置spi data引脚输入输出模式

SIMU_SPI_SDA_OUTPUT();

SIMU_SPI_SDA_INPUT();

四、设置spi NSS引脚高低（spi使能）

SPI_NSS_ACTIVE();//拉低开启使能

SPI_NSS_INACTIVE();//拉高关闭使能