ADS8695 STM32 硬件SPI驱动

SPI初始化配置

void my_spi1_init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_AHBPeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

	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_SetBits(GPIOA, GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7);
	spi1_cs_init();
	SPI1_Configuration();
	//SPI1_DMA_Configuration(DMA1_Channel2, (u32)&SPI1->DR, (u32)spi1_rx_buf, 0x00);
	//SPI1_DMA_Configuration(DMA1_Channel3, (u32)&SPI1->DR, (u32)spi1_tx_buf, 0x10);
}
void spi1_cs_init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure;
	RCC_AHBPeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC, ENABLE);

	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOA, &GPIO_InitStructure);

	// these two pin is for ads869x reset pin control
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOB, &GPIO_InitStructure);

	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_Init(GPIOC, &GPIO_InitStructure);

	GPIO_SetBits(GPIOA, GPIO_Pin_4);
	GPIO_SetBits(GPIOB, GPIO_Pin_0 | GPIO_Pin_1);
	GPIO_SetBits(GPIOC, GPIO_Pin_5);
	RST_AD1 = 0;
	RST_AD2 = 0;
	delay_ms(10);
	RST_AD1 = 1;
	RST_AD2 = 1;
}
void SPI1_Configuration(void)
{
	SPI_InitTypeDef SPI_InitStructure;
	SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
	SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;
	SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
	SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
	SPI_InitStructure.SPI_NSS = SPI_NSS_Hard;
	SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_32;
	SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
	SPI_InitStructure.SPI_CRCPolynomial = 7;

	SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
	SPI_Init(SPI1, &SPI_InitStructure);
	SPI_SSOutputCmd(SPI1, ENABLE);
	SPI_Cmd(SPI1, ENABLE);
}
void SPI1_DMA_Configuration(DMA_Channel_TypeDef *DMA_CHx, u32 src_addr, u32 des_buf, u8 direction)
{
	//1channel 2src_addr 3des_buf 4direction 5DMA_CMD
	DMA_InitTypeDef DMA_InitStructure;
	RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
	DMA_DeInit(DMA_CHx); //1

	DMA_InitStructure.DMA_PeripheralBaseAddr = src_addr;		    //2
	DMA_InitStructure.DMA_MemoryBaseAddr = des_buf;					//3
	DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC | direction;  //4
	DMA_InitStructure.DMA_BufferSize = 2;
	DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
	DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
	DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
	DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte; //8位
	DMA_InitStructure.DMA_Mode = DMA_Mode_Circular;
	DMA_InitStructure.DMA_Priority = DMA_Priority_High;
	DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;

	DMA_Init(DMA_CHx, &DMA_InitStructure);
	SPI_I2S_DMACmd(SPI1, SPI_I2S_DMAReq_Rx + (direction >> 4), ENABLE); //5
}

ADS8695初始化（仍然使用软件IO模拟方式发送初始化命令）

static u16 spi_16(u16 data)
{
	u8 i = 0;
	u16 result = 0;

	for (i = 0; i < 16; i++)
	{
		result = result << 1;
		if ((data & 0x8000) == 0x8000)
		{
			ads8695_MOSI = 1;
		}
		else
		{
			ads8695_MOSI = 0;
		}
		delay_us(50);
		ads8695_SCLK = 1;
		data = data << 1;
		if (ads8695_MISO != 0)
		{
			result = result | 0x01;
		}
		ads8695_SCLK = 0;
		delay_us(50);
	}
	return result;
}

u32 ads8695_reg_config(uint8_t command, uint16_t address, uint16_t data)
{
	u32 result = 0;
	u16 temp = 0;
	ads8695_CS = 0;
	delay_us(10);
	temp = (((command << 1) | ((address >> 8) & 1)) << 8) | (address & 0x00FF);
	result = spi_16(temp);
	result = (result << 16) | spi_16(data);
	delay_us(10);
	ads8695_CS = 1;
	return result;
}

Main函数 ADS8695值的硬件SPI方式读取

   void main()
{	
    my_spi1_init();
	ads8695_reg_config(ads8695_WRITE_FULL, ads8695_RANGE_SEL_REG, 0x08);
     while(1)
     {
    	CS_AD2 = 0;
    	delay_us(50);

    	test1 = spi1_read_write_byte(0);
    	test2 = spi1_read_write_byte(0);
    	test = test2 + (test1 << 8);
    	delay_us(50);
	    CS_AD2 = 1;
     }
}