上边是原理图，芯片一直没有恒流源的输出，转换标志DRDY脚的电平变化正常，但是数据跳动幅度较大。VCC和VCC_A不是同一个电源供电，都是3.3V。START脚接高电平，CLK引脚接地。请用过的朋友帮助看一下，因为恒流源设置的是1毫安电流，参考电阻正常应该有1.6V左右的电压，但是一直测不到电压，是电路有问题导致的芯片没有工作吗，着实弄不懂了。
附上我的代码：
ads1247.h
#ifndef __ADS1247_H
#define __ADS1247_H
#ifdef __cplusplus
extern "C" {
#endif
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "gpio.h"
/******************ads1247管脚与MCUSTM32F722对应关系**********
SCK(SPI2_SCK)-----------PB13
MISO(SPI2_MISO)---------PB14
MOSI(SPI2_MOSI)---------PB15 （SPI2）
NSS1(ADS_CS1)-----------PC0
NSS2(ADS_CS2)-----------PC2
NSS3(ADS_CS3)-----------PA4
NSS4(ADS_CS4)-----------PA6
NSS5(ADS_CS5)-----------PB0
NSS6(ADS_CS6)-----------PB12
DRDY1(PC1)---------PC1
DRDY2(PC3)---------PC3
DRDY3(PA5)---------PA5
DRDY4(PA7)---------PA7
DRDY5(PB1)---------PB1
DRDY6(PB2)---------PB2
******************ads1247管脚与MCU对应关系*******************/
//定义引脚有关宏函数
#define ADS_NSS1(n) (n?HAL_GPIO_WritePin(GPIOC,SPI2_NSS1_Pin,GPIO_PIN_SET):HAL_GPIO_WritePin(GPIOC,SPI2_NSS1_Pin,GPIO_PIN_RESET))
#define ADS_NSS2(n) (n?HAL_GPIO_WritePin(GPIOC,SPI2_NSS2_Pin,GPIO_PIN_SET):HAL_GPIO_WritePin(GPIOC,SPI2_NSS2_Pin,GPIO_PIN_RESET))
#define ADS_NSS3(n) (n?HAL_GPIO_WritePin(GPIOA,SPI2_NSS3_Pin,GPIO_PIN_SET):HAL_GPIO_WritePin(GPIOA,SPI2_NSS3_Pin,GPIO_PIN_RESET))
#define ADS_NSS4(n) (n?HAL_GPIO_WritePin(GPIOA,SPI2_NSS4_Pin,GPIO_PIN_SET):HAL_GPIO_WritePin(GPIOA,SPI2_NSS4_Pin,GPIO_PIN_RESET))
#define ADS_NSS5(n) (n?HAL_GPIO_WritePin(GPIOB,SPI2_NSS5_Pin,GPIO_PIN_SET):HAL_GPIO_WritePin(GPIOB,SPI2_NSS5_Pin,GPIO_PIN_RESET))
#define ADS_NSS6(n) (n?HAL_GPIO_WritePin(GPIOB,SPI2_NSS6_Pin,GPIO_PIN_SET):HAL_GPIO_WritePin(GPIOB,SPI2_NSS6_Pin,GPIO_PIN_RESET))
#define ADS_RDY6 HAL_GPIO_ReadPin( GPIOC,temp_RDY6_Pin )
/******************ads1247寄存器地址*******************/
#define ADS1247_CMD_WAKEUP 0x00//退出睡眠模式
#define ADS1247_CMD_SLEEP 0x02//进入睡眠模式
#define ADS1247_CMD_SYNC 0x04//同步A/D转换
#define ADS1247_CMD_RESET 0x06//上电复位值
#define ADS1247_CMD_NOP 0xff//空操作
#define ADS1247_CMD_RDATA 0x12//读一次数据
#define ADS1247_CMD_RDATAC 0x14//连续读取数据
#define ADS1247_CMD_SDATAC 0x16//停止连续读取数据
#define ADS1247_CMD_RREG 0x20//读寄存器
#define ADS1247_CMD_WREG 0x40//写寄存器
#define ADS1247_CMD_SYSOCAL 0x60//系统偏移校准
#define ADS1247_CMD_SYSGCAL 0x61//系统增益校准
#define ADS1247_CMD_SELFOCAL 0x62//自偏置校准
#define ADS1247_REG_MUX0 0x00//多路复用器控制寄存器0
#define ADS1247_REG_VBIAS 0x01//偏置电压寄存器
#define ADS1247_REG_MUX1 0x02//多路复用器控制寄存器1
#define ADS1247_REG_SYS0 0x03//系统控制寄存器
#define ADS1247_REG_CFC0 0x04//漂移校准系数寄存器0
#define ADS1247_REG_CFC1 0x05//漂移校准系数寄存器1
#define ADS1247_REG_CFC2 0x06//漂移校准系数寄存器2
#define ADS1247_REG_FSC0 0x07//满量程标准系数寄存器0
#define ADS1247_REG_FSC1 0x08//满量程标准系数寄存器1
#define ADS1247_REG_FSC2 0x09//满量程标准系数寄存器2
#define ADS1247_REG_IDAC0 0x0a//IDAC控制寄存器0
#define ADS1247_REG_IDAC1 0x0b//IDAC控制寄存器1
#define ADS1247_REG_GPIOCFG 0x0c//GPIO配置寄存器
#define ADS1247_REG_GPIODIR 0x0d//GPIO方向寄存器
#define ADS1247_REG_GPIODAT 0x0e//GPIO数据寄存器
/******************ads1247寄存器地址*******************/
//ADS1247支持的增益列表
#define ADC_GAIN_1 0x00
#define ADC_GAIN_2 0x10
#define ADC_GAIN_4 0x20
#define ADC_GAIN_8 0x30
#define ADC_GAIN_16 0x40
#define ADC_GAIN_32 0x50
#define ADC_GAIN_64 0x60
#define ADC_GAIN_128 0x70
//ADS1248支持的转换速率列表
#define ADC_SPS_5 0x00
#define ADC_SPS_10 0x01
#define ADC_SPS_20 0x02
#define ADC_SPS_40 0x03
#define ADC_SPS_80 0x04
#define ADC_SPS_160 0x05
#define ADC_SPS_320 0x06
#define ADC_SPS_640 0x07
#define ADC_SPS_1000 0x08
#define ADC_SPS_2000 0x09
//ADS124用于计算温度的参数
#define RREF 820.0f //参考电阻阻值REREF
#define RNOMINAL 100.0f //阻值R0
#define RTD_A 3.9083e-3 //IEC751规定
#define RTD_B -5.775e-7 //IEC751规定
//错误代码
#define ADS1247_OK ((uint8_t)0x00)
#define ADS1247_ERROR ((uint8_t)0x01)
#define ADS1247_BUSY ((uint8_t)0x02)
#define ADS1247_TIMEOUT ((uint8_t)0x03)
//函数定义，供主函数调用
void ADS1247_Init(void);
void ADS1247_WriteReg(uint8_t RegAddr,uint8_t *Buffer,uint8_t Length);
void ADS1247_ReadReg(uint8_t RegAddr,uint8_t *Buffer,uint8_t Length);
uint32_t ADS1247_ReadData_RTD(void);
float ADS1247_GetTempture(float *ReadTemp);
/* USER CODE END Prototypes */
#ifdef __cplusplus
}
#endif
#endif /*__ spi_H */
ads1247.c
#include "ADS1247.h"
#include "spi.h"
#include "math.h"
#include "stdio.h"
/*******************************************************************************
* Function Name : ADS1247_WriteCmd
* Description : 向外设1247写命令
* Input : Cmd
* Output :
*******************************************************************************/
static void ADS1247_WriteCmd(uint8_t Cmd)
{
ADS_NSS6(0);
HAL_SPI_Transmit(&hspi2,&Cmd,1,HAL_MAX_DELAY);
ADS_NSS6(1);
}
/*******************************************************************************
* Function Name : SPI_ADS1247_WriteReg
* Description : 写ADS1247的寄存器
* Input : 发送寄存器地址 发送数据字节
* Output :
*******************************************************************************/
void ADS1247_WriteReg(uint8_t RegAddr,uint8_t *Buffer,uint8_t Length)
{
uint8_t Cmd[2];
ADS_NSS6(0);
Cmd[0]=ADS1247_CMD_WREG|(RegAddr&0x0f);
Cmd[1]=(Length-1)&0x0f;
HAL_SPI_Transmit(&hspi2, Cmd, 2,HAL_MAX_DELAY); //指定向指定寄存器写入指定字节数据
HAL_SPI_Transmit(&hspi2, Buffer, Length,HAL_MAX_DELAY); //发送数据字节
ADS_NSS6(1);
}
/*******************************************************************************
* Function Name : ADS1247_ReadReg
* Description : 读寄存器
* Input : 发送寄存器地址 发送数据字节
* Output :
*******************************************************************************/
void ADS1247_ReadReg(uint8_t RegAddr,uint8_t *Buffer,uint8_t Length)
{
uint8_t Cmd[2];
ADS_NSS6(0);
Cmd[0]=ADS1247_CMD_RREG|(RegAddr&0x0f);
Cmd[1]=(Length-1)&0x0f;
HAL_SPI_Transmit(&hspi2,Cmd, 2,HAL_MAX_DELAY); //发送命令
HAL_SPI_Receive(&hspi2, Buffer, Length, HAL_MAX_DELAY);//接收寄存器数据
ADS_NSS6(1);
}
/*******************************************************************************
* Function Name : SPI_ADS1247_WaitBusy
* Description : 判断忙状态
* Input :
* Output :
*******************************************************************************/
void ADS1247_WaitBusy()
{
uint8_t i=0;
while(ADS_RDY6)
{
i++;
HAL_Delay(5);
if(i>200)
break;
}
}
/*******************************************************************************
* Function Name : ADS1247_Calibrate
* Description : ADS1247校准
* Input : None
* Output : None
* Return : None
*******************************************************************************/
//static uint8_t ADS1247_Calibrate(uint8_t Gain)
//{
// uint8_t R=0;
// uint8_t Cmd;
// ADS1247_WriteReg(ADS1247_REG_SYS0,&Gain,1); //设置增益和ADC输出速率
// Cmd=0x20; //0 01 00 000 启动内部参考电压，选择REF0作为参考电压输入；
// ADS1247_WriteReg(ADS1247_REG_MUX1,&Cmd,1);
//
// ADS1247_WriteCmd(ADS1247_CMD_SELFOCAL); //自偏校准
// R |= ADS1247_WaitBusy(); //等待完成
// Cmd=0x21; //0 01 00 001
// ADS1247_WriteReg(ADS1247_REG_MUX1,&Cmd,1); //设置系统监测外部参考电压偏移测量
//
// ADS1247_WriteCmd(ADS1247_CMD_SYSOCAL); //系统偏移校准
// R |= ADS1247_WaitBusy(); //等待完成
//
// Cmd=0x22; //设置系统监测外部参考电压偏移测量
// ADS1247_WriteReg(ADS1247_REG_MUX1,&Cmd,1);
//
// ADS1247_WriteCmd(ADS1247_CMD_SYSOCAL); //系统增益校准
// R |= ADS1247_WaitBusy(); //等待完成
// return R;
//}
/*******************************************************************************
* Function Name : ADS1247_Init
* Description : ADS1247初始化
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void ADS1247_Init()
{
uint8_t Cmd;
ADS_NSS6(0);
ADS1247_WriteCmd(ADS1247_CMD_RESET);
HAL_Delay(20);
Cmd=0x0A; //00 001 010 不开启传感器检测；选定输入通道组合P-AIN1，N-AIN2；
ADS1247_WriteReg(ADS1247_REG_MUX0,&Cmd,1);
Cmd=0x00; //0000 0110 不设置偏置电压
ADS1247_WriteReg(ADS1247_REG_VBIAS,&Cmd,1);
Cmd=0x20; //0 01 10 000 启动内部参考电压，选择REFP0:REFN0两端电压作为ADC参考电平
ADS1247_WriteReg(ADS1247_REG_MUX1,&Cmd,1);
Cmd=0x22; //0 010 0010 设置增益值、ADC输出数据率 4,20SPS
ADS1247_WriteReg(ADS1247_REG_SYS0,&Cmd,1);
// ADS1247_Calibrate(GainDataRate);
Cmd=0x06; //xxxxx 110 设置IDAC1=IDAC2电流源为1mA
ADS1247_WriteReg(ADS1247_REG_IDAC0,&Cmd,1);
Cmd=0x03; //0000 0011 控制电流源输出引脚 IDAC1->AIN0 IDAC2->AIN3.
ADS1247_WriteReg(ADS1247_REG_IDAC1,&Cmd,1);
Cmd=0x00; //GPIO3-AIN3 GPIO2-AIN2 GPIO1-REFN0 GPIO0-REFP0
ADS1247_WriteReg(ADS1247_REG_GPIOCFG,&Cmd,1);
Cmd=0x00; //
ADS1247_WriteReg(ADS1247_REG_GPIODIR,&Cmd,1);
Cmd=0x00; //
ADS1247_WriteReg(ADS1247_REG_GPIODAT,&Cmd,1);
// Delay_us(100);
ADS_NSS6(1);
}
/*******************************************************************************
* Function Name : ADS1247_ReadData_RTD
* Description : 连续读ADS1247 转换值
* Input : None
* Output : None
* Return : Register data
*******************************************************************************/
uint32_t ADS1247_ReadData_RTD(void)
{
uint8_t Cmd[4]={ADS1247_CMD_RDATA,ADS1247_CMD_NOP,ADS1247_CMD_NOP,ADS1247_CMD_NOP};
uint8_t Buf[4];
uint32_t Data=0;
ADS1247_WaitBusy();
ADS_NSS6(0);
HAL_SPI_TransmitReceive(&hspi2,Cmd,Buf,4,1000);
ADS_NSS6(1);
Data=Buf[1];
Data=(Data<<8)|Buf[2];
Data=(Data<<8)|Buf[3];
return Data;
}
