Other Parts Discussed in Thread: ADS1256,
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-1
ADS1255_SPI_WriteByte(0x00);
//向regaddr地址指向的寄存器写入数据databyte
ADS1255_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 ADS1255
CS_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 ADS1255
CS_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
