ADS1247: 读取寄存器的值总是不太正确, 读取十次寄存器值,后面九次都是正确的,第一次总是不正确.

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Part Number: ADS1247

这是spi初始化:

void InitSpi2(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
SPI_InitTypeDef SPI_InitStructure;

RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);//使能GPIOB时钟
RCC_APB1PeriphClockCmd(RCC_APB1Periph_SPI2, ENABLE);//使能SPI2时钟

//GPIOFB3,4,5初始化设置
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13|GPIO_Pin_14 | GPIO_Pin_15;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;//复用功能
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;//40MHz
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//上拉
GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;//PA4复用功能输出
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;//复用功能
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;//推挽输出
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;//40MHz
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//上拉
GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化
O_ADS1247_CS = 1;

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;//DRDY Pin
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
GPIO_Init(GPIOC, &GPIO_InitStructure);

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3 | GPIO_Pin_6;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_40MHz;
GPIO_Init(GPIOC, &GPIO_InitStructure);
O_ADS1247_Power = 1;
O_ADS1247_Rst = 1;
O_ADS1247_Start = 0;

GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource14, GPIO_AF_SPI2);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource15, GPIO_AF_SPI2);

SPI_I2S_DeInit(SPI2);

SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex; //设置SPI单向或者双向的数据模式:SPI设置为双线双向全双工
SPI_InitStructure.SPI_Mode = SPI_Mode_Master; //设置SPI工作模式:设置为主SPI
SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b; //设置SPI的数据大小:SPI发送接收8位帧结构
SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;//SPI_CPOL_High; //串行同步时钟的空闲状态为高电平
SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge; //串行同步时钟的第二个跳变沿(上升或下降)数据被采样
SPI_InitStructure.SPI_NSS = SPI_NSS_Soft; //NSS信号由硬件(NSS管脚)还是软件(使用SSI位)管理:内部NSS信号有SSI位控制
SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; //定义波特率预分频的值:波特率预分频值为256
SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB; //指定数据传输从MSB位还是LSB位开始:数据传输从MSB位开始
SPI_InitStructure.SPI_CRCPolynomial = 7; //CRC值计算的多项式
SPI_Init(SPI2, &SPI_InitStructure); //根据SPI_InitStruct中指定的参数初始化外设SPIx寄存器

SPI_Cmd(SPI2, ENABLE); //使能SPI外设
// SPI2_WriteBytes(0xff,1);
}

这是读写寄存器的程序:

void ADS1247_RWSYSReg()
{
uint8_t Data[10]={0};
unsigned char i=0;

O_ADS1247_CS = 0;//ADS1247_CLR_CS;
O_ADS1247_Start = 1;//ADS1247_SET_START;
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI2, 0x42); // 写 SYS0 寄存器
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI2, 0x00); // 写 1 个寄存器
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI2, 0x21); // 向 SYS0 寄存器写入 0x05, (PGA=1,160SPS)
// while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
// SPI_I2S_SendData(SPI2,0xFF);
for(i = 0; i < 10; i++) // 连续读寄存器10次
{
Delay_us(100);
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI2,0x22);
Delay_us(100);
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI2,0x00);
Delay_us(100);
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI2,0xFF);
while(SPI_I2S_GetFlagStatus(SPI2, SPI_I2S_FLAG_RXNE) == RESET);
Data[i] = SPI_I2S_ReceiveData(SPI2);
}
__breakpoint(0);
O_ADS1247_CS = 1;//ADS1247_SET_CS;
}