STM32F103SPI驱动ADS1256

ADS1256是一款高精度、低功耗的24位模数转换器（ADC），常用于电子测量、仪器仪表、传感器接口等领域。STM32F103是一款基于ARM Cortex-M3内核的微控制器，拥有丰富的外设资源，其中包括SPI接口。

为了驱动ADS1256，我们需要通过SPI接口与其进行通信。以下是基于STM32F103的ADS1256驱动程序示例：

首先，我们需要定义一些常量和变量：

#define ADS1256_SPI SPI1
#define ADS1256_CS GPIO_Pin_4

#define ADS1256_START 0x08
#define ADS1256_WAKEUP 0x00
#define ADS1256_RDATA 0x01
#define ADS1256_RDATAC 0x03
#define ADS1256_SDATAC 0x0F
#define ADS1256_RREG 0x10
#define ADS1256_WREG 0x50
#define ADS1256_SELFCAL 0xF0
#define ADS1256_SELFOCAL 0xF1
#define ADS1256_SELFGCAL 0xF2
#define ADS1256_SYSOCAL 0xF3
#define ADS1256_SYSGCAL 0xF4
#define ADS1256_SYNC 0xFC
#define ADS1256_STANDBY 0xFD
#define ADS1256_RESET 0xFE

uint8_t ADS1256_Buffer[3];

这里定义了SPI接口、ADS1256的CS引脚、ADS1256的指令常量以及一个用于缓存数据的数组。

接着，我们需要实现SPI的初始化函数：

void ADS1256_SPI_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    SPI_InitTypeDef SPI_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = ADS1256_CS;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
    SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
    SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_64;
    SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
    SPI_Init(ADS1256_SPI, &SPI_InitStructure);

    SPI_Cmd(ADS1256_SPI, ENABLE);

    ADS1256_CS_HIGH();
}

该函数首先初始化GPIO和SPI外设，并将ADS1256的CS引脚设置为输出模式。然后设置SPI的工作模式、传输速率等参数，并使能SPI外设。

接下来，我们可以编写一个函数用于向ADS1256发送指令：

void ADS1256_SendCommand(uint8_t command)
{
    ADS1256_CS_LOW();

    SPI_I2S_SendData(ADS1256_SPI, command);
    while (SPI_I2S_GetFlagStatus(ADS1256_SPI, SPI_I2S_FLAG_BSY) == SET);

    ADS1256_CS_HIGH();
}

该函数将ADS1256的CS引脚拉低，发送指令，等待传输完成，然后将CS引脚拉高。

接着，我们可以编写一个函数用于向ADS1256写寄存器：

void ADS1256_WriteReg(uint8_t reg, uint8_t data)
{
    ADS1256_CS_LOW();

    ADS1256_Buffer[0] = ADS1256_WREG | reg;
    ADS1256_Buffer[1] = 0x00;
    ADS1256_Buffer[2] = data;

    SPI_I2S_SendData(ADS1256_SPI, ADS1256_Buffer[0]);
    while (SPI_I2S_GetFlagStatus(ADS1256_SPI, SPI_I2S_FLAG_BSY) == SET);

    SPI_I2S_SendData(ADS1256_SPI, ADS1256_Buffer[1]);
    while (SPI_I2S_GetFlagStatus(ADS1256_SPI, SPI_I2S_FLAG_BSY) == SET);

    SPI_I2S_SendData(ADS1256_SPI, ADS1256_Buffer[2]);
    while (SPI_I2S_GetFlagStatus(ADS1256_SPI, SPI_I2S_FLAG_BSY) == SET);

    ADS1256_CS_HIGH();
}

该函数首先将ADS1256的CS引脚拉低，然后发送写寄存器指令和寄存器地址。接着，发送两个字节的数据，等待传输完成，最后将CS引脚拉高。

最后，我们可以编写一个函数用于从ADS1256读取数据：

int32_t ADS1256_ReadData(void)
{
    uint32_t i;
    uint32_t timeout = 100000;

    ADS1256_CS_LOW();

    ADS1256_Buffer[0] = ADS1256_RDATA;

    SPI_I2S_SendData(ADS1256_SPI, ADS1256_Buffer[0]);
    while (SPI_I2S_GetFlagStatus(ADS1256_SPI, SPI_I2S_FLAG_BSY) == SET);

    for (i = 0; i < 3; i++)
    {
        timeout = 100000;
        while (SPI_I2S_GetFlagStatus(ADS1256_SPI, SPI_I2S_FLAG_RXNE) == RESET)
        {
            if (--timeout == 0)
            {
                ADS1256_CS_HIGH();
                return 0;
            }
        }
        ADS1256_Buffer[i] = SPI_I2S_ReceiveData(ADS1256_SPI);
    }

    ADS1256_CS_HIGH();

    return ((int32_t)ADS1256_Buffer[0] << 16) | ((int32_t)ADS1256_Buffer[1] << 8) | ((int32_t)ADS1256_Buffer[2]);
}

该函数首先将ADS1256的CS引脚拉低，然后发送读数据指令。接着，循环读取三个字节的数据，等待传输完成，最后将CS引脚拉高。返回值为读取到的数据的24位有符号整数值。

以上就是基于STM32F103的ADS1256驱动程序示例。需要注意的是，该示例仅提供了基本的SPI通信和指令发送功能，具体的应用需要根据实际情况进行修改和完善。