ADS1255: 寄存器能够读取，但是写入一直有问题，不知道是什么情况

电路图如上,我使用的芯片是STM32F103VCT6，SPI选的是SPI1 ，引脚分别为PA5、PA6、PA7。

使用标准库开发，这个是初始化代码

void ADS1255_SPI_Configuration(void)
{
	SPI_InitTypeDef SPI_InitStructure;
	GPIO_InitTypeDef GPIO_InitStructure;

	/****Initial SPI1******************/

	/* Enable SPI1 and GPIOA clocks */
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE); // GPIOA 时钟使能
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);  // SPI1 时钟使能

	/* Configure SPI1 pins: SCK, MISO and MOSI */
	GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7; // PA5: SCK, PA6: MISO, PA7: MOSI
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; // 复用推挽模式
	GPIO_Init(GPIOA, &GPIO_InitStructure);

	/* SPI1 configuration */
	SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;	 // SPI1设置为两线全双工
	SPI_InitStructure.SPI_Mode = SPI_Mode_Master;// 设置SPI1为主模式
	SPI_InitStructure.SPI_DataSize = SPI_DataSize_8b;// SPI发送接收8位帧结构
	SPI_InitStructure.SPI_CPOL = SPI_CPOL_Low;// 串行时钟在不操作时，时钟为低电平
	SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;// 第二个时钟沿开始采样数据
	SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;// NSS信号由软件（使用SSI位）管理
	SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_256; // 定义波特率预分频的值
	SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;// 数据传输从MSB位开始
	SPI_InitStructure.SPI_CRCPolynomial = 7;// CRC值计算的多项式
	SPI_Init(SPI1, &SPI_InitStructure);

	/* Enable SPI1 */
	SPI_Cmd(SPI1, ENABLE);
}

SPI通信的代码

unsigned char ADS1255_SPI_WriteByte(unsigned char TxData)
{unsigned char RxData = 0;
	/* 等待 SPI TXE 标志，确保上一次数据传输完成 */while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
	/* 发送数据到 SPI 总线 */SPI_I2S_SendData(SPI1, TxData);
	/* 等待 SPI RXNE 标志，确保接收到数据 */while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
	/* 读取 SPI 总线返回的数据 */RxData = SPI_I2S_ReceiveData(SPI1);return RxData;
}

这个是ADS的主体驱动

#include <stdio.h>
#include "ads1255.h"

//初始化ADS1256 GPIO
void Init_ADS1256_GPIO(void)
{GPIO_InitTypeDef GPIO_InitStructure;
	RCC_APB2PeriphClockCmd(RCC_DRDY, ENABLE); 

	GPIO_InitStructure.GPIO_Pin = PIN_DRDY;	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;	GPIO_Init(PORT_DRDY, &GPIO_InitStructure);//SPI1 NSS 
	CS_1();GPIO_InitStructure.GPIO_Pin = PIN_CS;GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;GPIO_Init(PORT_CS, &GPIO_InitStructure);
	ADS1255_SPI_Configuration();
}

//-----------------------------------------------------------------//
//	功能：ADS1256 写数据
//	入口参数: /
//	出口参数: /
//	全局变量: /
//	备注: 向ADS1256中地址为regaddr的寄存器写入一个字节databyte
//-----------------------------------------------------------------//
void ADS1256WREG(unsigned char regaddr,unsigned char databyte)
{
	CS_0();
	while(ADS1256_DRDY);//当ADS1256_DRDY为低时才能写寄存器
	//向寄存器写入数据地址ADS1255_SPI_WriteByte(ADS1256_CMD_WREG | (regaddr & 0x0F));//写入数据的个数n-1ADS1255_SPI_WriteByte(0x00);//向regaddr地址指向的寄存器写入数据databyteADS1255_SPI_WriteByte(databyte);
	CS_1();
}


//初始化ADS1256
void ADS1256_Init(void)
{
	ADS1256_Reset();
	ADS1256_ReadAllRegisters();
	ADS1256WREG(ADS1256_STATUS,0x06);// 高位在前、使用缓冲
//	ADS1256WREG(ADS1256_STATUS,0x04);// 高位在前、不使用缓冲
	ADS1256WREG(ADS1256_MUX,0x08);// 初始化端口A0为‘+’，AINCOM位‘-’
	ADS1256WREG(ADS1256_ADCON,ADS1256_GAIN_1);// 放大倍数1
	ADS1256WREG(ADS1256_DRATE,ADS1256_DRATE_10SPS);  // 数据10sps
	ADS1256WREG(ADS1256_IO,0x00);

	//*************自校准****************	while(ADS1256_DRDY);
	CS_0();
	ADS1255_SPI_WriteByte(ADS1256_CMD_SELFCAL);
	while(ADS1256_DRDY);
	CS_1();
	//**********************************

	ADS1256_ReadAllRegisters();
}

//读取AD值
signed int ADS1256ReadData(unsigned char channel)  
{unsigned int sum=0;
	
	while(ADS1256_DRDY);//当ADS1256_DRDY为低时才能写寄存器 
	ADS1256WREG(ADS1256_MUX,channel);		//设置通道
	CS_0();
	ADS1255_SPI_WriteByte(ADS1256_CMD_SYNC);
	ADS1255_SPI_WriteByte(ADS1256_CMD_WAKEUP);
	ADS1255_SPI_WriteByte(ADS1256_CMD_RDATA);	sum |= (ADS1255_SPI_WriteByte(0xff) << 16);
	sum |= (ADS1255_SPI_WriteByte(0xff) << 8);
	sum |= ADS1255_SPI_WriteByte(0xff);
	CS_1();

	if (sum>0x7FFFFF)// if MSB=1, 
	{
		sum -= 0x1000000;// do 2's complement

	}return sum;
}

void ADS1256_ReadAllRegisters(void)
{uint8_t reg_values[11]; // ADS1255 一共有 11 个寄存器
	int i = 0;const char *reg_names[] = {"STATUS", "MUX", "ADCON", "DRATE", "IO","OFC0", "OFC1", "OFC2", "FSC0", "FSC1", "FSC2"};printf("Reading all ADS1255 registers:\n");// 选中 ADS1255CS_0();// 发送读取命令（起始寄存器 0x00，读取 11 个寄存器）ADS1255_SPI_WriteByte(ADS1256_CMD_RREG | 0x00);ADS1255_SPI_WriteByte(0x0A); // 需要读取 (11-1) 个寄存器// 依次读取 11 个寄存器的值for (i = 0; i < 11; i++){reg_values[i] = ADS1255_SPI_WriteByte(0xFF); // 读取 SPI 总线返回的值printf("%s (0x%02X) = 0x%02X\n", reg_names[i], i, reg_values[i]);}// 释放 ADS1255CS_1();
}

void ADS1256_Reset(void)
{CS_0();ADS1255_SPI_WriteByte(ADS1256_CMD_REST);  // 发送复位命令Delay_ms(5); // 等待复位完成（至少 0.6ms）CS_1();
}

在调用完这个初始化的函数后，打印的两次寄存器的值如下

Reading all ADS1255 registers:
STATUS (0x00) = 0x30
MUX (0x01) = 0x01
ADCON (0x02) = 0x20
DRATE (0x03) = 0xF0
IO (0x04) = 0xE1
OFC0 (0x05) = 0x36
OFC1 (0x06) = 0xFA
OFC2 (0x07) = 0xFF
FSC0 (0x08) = 0xF4
FSC1 (0x09) = 0x16
FSC2 (0x0A) = 0x45
Reading all ADS1255 registers:
STATUS (0x00) = 0x36
MUX (0x01) = 0x01
ADCON (0x02) = 0x20
DRATE (0x03) = 0xF0
IO (0x04) = 0xE1
OFC0 (0x05) = 0x45
OFC1 (0x06) = 0xFA
OFC2 (0x07) = 0xFF
FSC0 (0x08) = 0x8D
FSC1 (0x09) = 0xAC
FSC2 (0x0A) = 0x50

现在不知道为啥会写入不进去啊，求求TI的技术人员能帮我看看

Daniel：

您好

已经收到了您的案例，调查需要些时间，感谢您的耐心等待

,

Alice：

您好，

      请先去掉ADS1256_Reset(); 直接读取寄存器，确认芯片上电复位正常。

      ADC上电初始化后，读取的的STATUS (0x00)的值是不对的，DRDY应该为1.

     

      

      Very Low Noise, 24-Bit Analog-to-Digital Converter datasheet (Rev. K)