[嵌入式]STM32软硬件SPI读取MAX31865 PT100温度支持shell功能

? ? ? ? PT100的温度读取硬件是利用TB的MAX31865现成模块，也可以自己做相应的PCB。原理图可以查看美信官方文档作为参考。传送门：https://www.maximintegrated.com/en/products/interface/sensor-interface/MAX31865.html

????????STM32的SPI功能就不多赘述，可以利用软件模拟SPI或使用STM32的硬件SPI。相应的优缺点个人使用总结单个SPI通讯用软硬件都行，多机通讯使用STM32的硬件SPI较好。

????????下面将展示STM32软硬件SPI读取MAX31865，获得电阻值计算温度的模块代码。

????????百度云链接：https://pan.baidu.com/s/1B8qxTVGqyX6V1TCjKcCfrQ?
????????提取码：fq7g

显示效果如下：

?

软件模拟SPI读取MAX31865，转换为温度输出。

#include "max31865.h"

/***********************************************
调用方式：MAX31865_Init()
返回值：
SDO   --->   PC10
CS    --->   PC12
SCLK  --->   PC9
SDI   --->   PC11
DRDY  --->   PC13
函数说明：MAX31865 初始化,软件模拟
************************************************/
void MAX31865_Init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure ;

	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_GPIOB|RCC_APB2Periph_GPIOA,ENABLE);

	GPIO_InitStructure.GPIO_Pin = MAX31865_CS|MAX31865_SCLK|MAX31865_SDI;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_Init(MAX31865_CONTROL_PORT,&GPIO_InitStructure);
	
	GPIO_InitStructure.GPIO_Pin = MAX31865_SDO|MAX31865_DRDY;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_Init(MAX31865_CONTROL_PORT,&GPIO_InitStructure);
	
	MAX31865_CS_SET;
	MAX31865_SCLK_SET;
}

/***********************************************
调用方式：MAX31865_Write()
返回值：
函数说明：MAX31865 写寄存器,addr:寄存器地址,data:数据
************************************************/
void MAX31865_Write(unsigned char addr, unsigned char data)
{
		unsigned char i;
	
	MAX31865_CS_CLR;
	for(i=0;i<8;i++)  //写地址
	{
		MAX31865_SCLK_CLR;
		if(addr&0x80) MAX31865_SDI_SET;
		else MAX31865_SDI_CLR;
		MAX31865_SCLK_SET;
		addr<<=1;
	}
	for(i=0;i<8;i++)  //写数据
	{
		MAX31865_SCLK_CLR;
		if(data&0x80) MAX31865_SDI_SET;
		else MAX31865_SDI_CLR;
		MAX31865_SCLK_SET;
		data<<=1;
	}
	MAX31865_CS_SET;
}
/***********************************************
调用方式：MAX31865_Read()
返回值：  data
函数说明：MAX31865 读寄存器 ,addr:寄存器地址
************************************************/
unsigned char MAX31865_Read(unsigned char addr)
{
	unsigned char i;
	unsigned char data=0;
	
	MAX31865_CS_CLR;
	for(i=0;i<8;i++)  //写地址
	{
		MAX31865_SCLK_CLR;
		if(addr&0x80) MAX31865_SDI_SET;
		else MAX31865_SDI_CLR;
		MAX31865_SCLK_SET;
		addr<<=1;
	}
	for(i=0;i<8;i++)  //读数据
	{
		MAX31865_SCLK_CLR;
		data<<=1;		
		MAX31865_SCLK_SET;		
		if(MAX31865_SDO_READ) data|=0x01;
		else data|=0x00;
	}
	MAX31865_CS_SET;
	return data;
}
/***********************************************
调用方式：MAX31865_Cfg()
返回值：  
函数说明：MAX31865 配置
************************************************/
void MAX31865_Cfg(void)
{
	//BIAS ON,自动，4线，50HZ  根据文件修改四线还是三线
	MAX31865_Write(0x80, 0xC3); 
}
/***********************************************
调用方式：MAX31865_GetTemp()
返回值：  
函数说明：MAX31865 获取温度
************************************************/
float MAX31865_GetTemp(void)
{ 
	unsigned int data;
	float Rt;
	float Rt0 = 100;  //PT100	
	float Z1,Z2,Z3,Z4,temp;
	float a = 3.9083e-3;
	float b = -5.775e-7;
	float rpoly;
//	MAX31865_Write(0x80, 0xD3);
	data=MAX31865_Read(0x01)<<8;
	data|=MAX31865_Read(0x02);
	data>>=1;  //去掉Fault位
	Rt=(float)data/32768.0*RREF;
	Z1 = -a;
  Z2 = a*a-4*b;
  Z3 = 4*b/Rt0;
  Z4 = 2*b;
  temp = Z2+Z3*Rt;
  temp = (sqrt(temp)+Z1)/Z4;
  if(temp>=0){
		return temp;
	}
  rpoly = Rt;
  temp = -242.02;
  temp += 2.2228 * rpoly;
  rpoly *= Rt;  // square
  temp += 2.5859e-3 * rpoly;
  rpoly *= Rt;  // ^3
  temp -= 4.8260e-6 * rpoly;
  rpoly *= Rt;  // ^4
  temp -= 2.8183e-8 * rpoly;
  rpoly *= Rt;  // ^5
  temp += 1.5243e-10 * rpoly;

  return temp;
}

#ifndef __MAX31865_H
#define __MAX31865_H

#include "stm32f10x.h"
#include "math.h"
#include "usart_arb.h"
#include "delay.h"

/* MAX31865参考电阻 */
#define RREF            (430)  //400Ω


/* MAX31865控制口 */
#define MAX31865_CONTROL_PORT     GPIOC
#define MAX31865_SDO              GPIO_Pin_10
#define MAX31865_CS               GPIO_Pin_12
#define MAX31865_SCLK             GPIO_Pin_9
#define MAX31865_SDI              GPIO_Pin_11
#define MAX31865_DRDY 	          GPIO_Pin_13 

#define MAX31865_CS_SET           GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_CS,Bit_SET)
#define MAX31865_CS_CLR      		  GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_CS,Bit_RESET)
#define MAX31865_SCLK_SET    			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SCLK,Bit_SET)
#define MAX31865_SCLK_CLR    			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SCLK,Bit_RESET)
#define MAX31865_SDI_SET    			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SDI,Bit_SET)
#define MAX31865_SDI_CLR     			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SDI,Bit_RESET)

#define MAX31865_SDO_READ    			GPIO_ReadInputDataBit(MAX31865_CONTROL_PORT,MAX31865_SDO)
#define MAX31865_DRDY_READ   			GPIO_ReadInputDataBit(MAX31865_CONTROL_PORT,MAX31865_DRDY)

void MAX31865_Init(void); //MAX31865 初始化,软件模拟
void MAX31865_Cfg(void);  //MAX31865 配置
float MAX31865_GetTemp(void);//MAX31865 获取温度


#endif

硬件SPI读取MAX31865，转换为温度输出。?

#include "stm32_spi.h"

__IO uint32_t TIMEOUT=LONG_TIMEOUT;
/***********************************************
调用方式： SPI_Inital()
SDO   --->   PA5
CS    --->   PB6
SCLK  --->   PA5
SDI   --->   PA7
DRDY  --->   PB6
返回值：  
函数说明：MAX31865 硬件spi初始化
************************************************/
void  SPI_Inital(void)
{
 SPI_InitTypeDef  SPI_InitStructure;
 GPIO_InitTypeDef  GPIO_InitStructure; 
// GPIO
 RCC_APB2PeriphClockCmd(SPI_GPIO_CLK, ENABLE);
 RCC_APB2PeriphClockCmd(SPI_CS_GPIO_CLK, ENABLE);

 /*!< SPI Periph clock enable */
 RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
 
 /*!< GPIO configuration */  
 /*!< Configure SPI pins */
 GPIO_InitStructure.GPIO_Pin = SPI_SCK|SPI_MOSI|SPI_MISO;
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
 GPIO_Init(MAX31865_SPI_PORT, &GPIO_InitStructure);
 
 /*!< Configure SPI pin: CS */
 GPIO_InitStructure.GPIO_Pin = SPI_CS;
 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
 GPIO_Init(MAX31865_IO_PORT, &GPIO_InitStructure);  
 //set CS high
	GPIO_SetBits(MAX31865_IO_PORT, SPI_CS); 
 /*!< SPI configuration */
 SPI_InitStructure.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
 SPI_InitStructure.SPI_Mode = SPI_Mode_Master;
 SPI_InitStructure.SPI_DataSize =SPI_DataSize_8b;
 SPI_InitStructure.SPI_CPOL = SPI_CPOL_High;
 SPI_InitStructure.SPI_CPHA = SPI_CPHA_2Edge;
 SPI_InitStructure.SPI_NSS = SPI_NSS_Soft;
 SPI_InitStructure.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_8;
 SPI_InitStructure.SPI_FirstBit = SPI_FirstBit_MSB;
 SPI_InitStructure.SPI_CRCPolynomial = 7;
 /* SPI Peripheral Enable */
 SPI_Cmd(SPI1, ENABLE);
 /* Apply SPI configuration after enabling it */
 SPI_Init(SPI1, &SPI_InitStructure);
}
/***********************************************
调用方式： SPI_Write()
返回值：  
函数说明：SPI写数据
************************************************/
uint8_t SPI_Write(uint8_t *buffer, uint8_t nBytes)
{
  uint8_t i;
  for(i=0;i<nBytes;i++){
       TIMEOUT = LONG_TIMEOUT;
       while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET){  //not empty
                if((TIMEOUT--) == 0) return (1);
             }
       SPI_I2S_SendData(SPI1,buffer[i]);
       TIMEOUT = LONG_TIMEOUT;
       while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET){     
               if((TIMEOUT--) == 0) return (1);
            }
       SPI_I2S_ReceiveData(SPI1);  
     }
  return(0);
}
/***********************************************
调用方式： SPI_Read()
返回值：  
函数说明：SPI读数据
************************************************/
uint8_t SPI_Read(uint8_t *buffer, uint8_t nBytes)
{
  uint8_t i;
  SPI_I2S_ReceiveData(SPI1);
  for(i=0;i<nBytes;i++)
     {
       TIMEOUT = LONG_TIMEOUT;
       while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET){  //not empty
               if((TIMEOUT--) == 0) return (1);
             }
       SPI_I2S_SendData(SPI1,0x00);
       TIMEOUT = LONG_TIMEOUT;
       while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET){
               if((TIMEOUT--) == 0) return (1);
            }
       buffer[i]= SPI_I2S_ReceiveData(SPI1);
     }
  return(0);
}
/***********************************************
调用方式： SPI_WriteByte()
返回值：  
函数说明：SPI字节写数据
************************************************/
uint8_t SPI_WriteByte(uint8_t data)
{
	 TIMEOUT = LONG_TIMEOUT;
	 while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET){  //not empty
						if((TIMEOUT--) == 0) return (1);
				 }
	 SPI_I2S_SendData(SPI1,data);
	 TIMEOUT = LONG_TIMEOUT;
	 while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET){
					 if((TIMEOUT--) == 0) return (1);
				}
	 SPI_I2S_ReceiveData(SPI1);
	 SPI_I2S_ReceiveData(SPI1);
	 return(0);
}
/***********************************************
调用方式： SPI_WriteByte()
返回值：  
函数说明：SPI字节读数据
************************************************/
uint8_t SPI_ReadByte(void)
{
	SPI_I2S_ReceiveData(SPI1);
	while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);  //not empty	
	SPI_I2S_SendData(SPI1,0xff);
	while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET); 
	return (SPI_I2S_ReceiveData(SPI1));
}
/***********************************************
调用方式： Set_DRDY_Pin_INPUT()
返回值：  
函数说明：MAX31865 DRDY输入IO配置
************************************************/
void Set_DRDY_Pin_INPUT(void)
{
   GPIO_InitTypeDef  GPIO_InitStructure;
   
   RCC_APB2PeriphClockCmd(DRDY_GPIO_CLK, ENABLE); 
   GPIO_InitStructure.GPIO_Pin = DRDY_PIN;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
   GPIO_Init(MAX31865_IO_PORT, &GPIO_InitStructure);      
}
/***********************************************
调用方式： DRDY_Pin_Value()
返回值：  
函数说明： 读MAX31865  DRDY_Pin_Value高低电平
************************************************/
uint8_t DRDY_Pin_Value(void)
{
   return(GPIO_ReadOutputDataBit(MAX31865_IO_PORT, DRDY_PIN));      
}

#ifndef __STM32_SPI_H
#define __STM32_SPI_H

#ifdef __cplusplus
 extern "C" {
#endif

/* Includes ------------------------------------------------------------------*/
#include "stm32f10x.h"
   
#define FLAG_TIMEOUT         ((uint32_t)0x1000)
#define LONG_TIMEOUT         ((uint32_t)(10 *FLAG_TIMEOUT))

#define MAX31865_SPI_PORT 				GPIOA
#define MAX31865_IO_PORT  				GPIOB
				
// define SPI pins				
#define SPI_SCK           				GPIO_Pin_5    /* GPIOA.5*/
#define SPI_MISO          				GPIO_Pin_6    /*GPIOA.6*/
#define SPI_MOSI          				GPIO_Pin_7    /*GPIOA.7*/
#define SPI_CS            				GPIO_Pin_6    /*GPIOB.6*/
#define DRDY_PIN          				GPIO_Pin_5    /*GPIOB.5*/

#define SPI_GPIO_CLK             	RCC_APB2Periph_GPIOA
#define SPI_CS_GPIO_CLK          	RCC_APB2Periph_GPIOB
#define DRDY_GPIO_CLK            	RCC_APB2Periph_GPIOB


#define SPI_CS_HIGH              	GPIO_SetBits(MAX31865_IO_PORT, SPI_CS)
#define SPI_CS_LOW               	GPIO_ResetBits(MAX31865_IO_PORT, SPI_CS)

void  SPI_Inital(void);//MAX31865 硬件spi初始化
uint8_t SPI_Write(uint8_t *buffer, uint8_t nBytes);//SPI写数据
uint8_t SPI_Read(uint8_t *buffer, uint8_t nBytes); //SPI读数据 
uint8_t SPI_WriteByte(uint8_t data);//SPI字节写数据
uint8_t SPI_ReadByte(void);         //SPI字节读数据
void Set_DRDY_Pin_INPUT(void);//MAX31865 DRDY输入IO配置
uint8_t DRDY_Pin_Value(void);//读MAX31865  DRDY_Pin_Value高低电平

#ifdef __cplusplus
}
#endif

#endif

#include "max31865.h"

/***********************************************
调用方式：MAX31865_Init()
返回值：
SDO   --->   PC10
CS    --->   PC12
SCLK  --->   PC9
SDI   --->   PC11
DRDY  --->   PC13
函数说明：MAX31865 初始化,软件模拟
************************************************/
void MAX31865_Init(void)
{
	GPIO_InitTypeDef GPIO_InitStructure ;

	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC|RCC_APB2Periph_GPIOB|RCC_APB2Periph_GPIOA,ENABLE);

	GPIO_InitStructure.GPIO_Pin = MAX31865_CS|MAX31865_SCLK|MAX31865_SDI;
	GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
	GPIO_Init(MAX31865_CONTROL_PORT,&GPIO_InitStructure);
	
	GPIO_InitStructure.GPIO_Pin = MAX31865_SDO|MAX31865_DRDY;
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
	GPIO_Init(MAX31865_CONTROL_PORT,&GPIO_InitStructure);
	
	MAX31865_CS_SET;
	MAX31865_SCLK_SET;
}

/***********************************************
调用方式：MAX31865_Write()
返回值：
函数说明：MAX31865 写寄存器,addr:寄存器地址,data:数据
************************************************/
void MAX31865_Write(unsigned char addr, unsigned char data)
{
		unsigned char i;
	
	MAX31865_CS_CLR;
	for(i=0;i<8;i++)  //写地址
	{
		MAX31865_SCLK_CLR;
		if(addr&0x80) MAX31865_SDI_SET;
		else MAX31865_SDI_CLR;
		MAX31865_SCLK_SET;
		addr<<=1;
	}
	for(i=0;i<8;i++)  //写数据
	{
		MAX31865_SCLK_CLR;
		if(data&0x80) MAX31865_SDI_SET;
		else MAX31865_SDI_CLR;
		MAX31865_SCLK_SET;
		data<<=1;
	}
	MAX31865_CS_SET;
}
/***********************************************
调用方式：MAX31865_Read()
返回值：  data
函数说明：MAX31865 读寄存器 ,addr:寄存器地址
************************************************/
unsigned char MAX31865_Read(unsigned char addr)
{
	unsigned char i;
	unsigned char data=0;
	
	MAX31865_CS_CLR;
	for(i=0;i<8;i++)  //写地址
	{
		MAX31865_SCLK_CLR;
		if(addr&0x80) MAX31865_SDI_SET;
		else MAX31865_SDI_CLR;
		MAX31865_SCLK_SET;
		addr<<=1;
	}
	for(i=0;i<8;i++)  //读数据
	{
		MAX31865_SCLK_CLR;
		data<<=1;		
		MAX31865_SCLK_SET;		
		if(MAX31865_SDO_READ) data|=0x01;
		else data|=0x00;
	}
	MAX31865_CS_SET;
	return data;
}
/***********************************************
调用方式：MAX31865_Cfg()
返回值：  
函数说明：MAX31865 配置
************************************************/
void MAX31865_Cfg(void)
{
	//BIAS ON,自动，4线，50HZ  根据文件修改四线还是三线
	MAX31865_Write(0x80, 0xC3); 
}
/***********************************************
调用方式：MAX31865_GetTemp()
返回值：  
函数说明：MAX31865 获取温度
************************************************/
float MAX31865_GetTemp(void)
{ 
	unsigned int data;
	float Rt;
	float Rt0 = 100;  //PT100	
	float Z1,Z2,Z3,Z4,temp;
	float a = 3.9083e-3;
	float b = -5.775e-7;
	float rpoly;
//	MAX31865_Write(0x80, 0xD3);
	data=MAX31865_Read(0x01)<<8;
	data|=MAX31865_Read(0x02);
	data>>=1;  //去掉Fault位
	Rt=(float)data/32768.0*RREF;
	Z1 = -a;
  Z2 = a*a-4*b;
  Z3 = 4*b/Rt0;
  Z4 = 2*b;
  temp = Z2+Z3*Rt;
  temp = (sqrt(temp)+Z1)/Z4;
  if(temp>=0){
		return temp;
	}
  rpoly = Rt;
  temp = -242.02;
  temp += 2.2228 * rpoly;
  rpoly *= Rt;  // square
  temp += 2.5859e-3 * rpoly;
  rpoly *= Rt;  // ^3
  temp -= 4.8260e-6 * rpoly;
  rpoly *= Rt;  // ^4
  temp -= 2.8183e-8 * rpoly;
  rpoly *= Rt;  // ^5
  temp += 1.5243e-10 * rpoly;

  return temp;
}

#ifndef __MAX31865_H
#define __MAX31865_H

#include "stm32f10x.h"
#include "math.h"
#include "usart_arb.h"
#include "delay.h"

/* MAX31865参考电阻 */
#define RREF            (430)  //400Ω


/* MAX31865控制口 */
#define MAX31865_CONTROL_PORT     GPIOC
#define MAX31865_SDO              GPIO_Pin_10
#define MAX31865_CS               GPIO_Pin_12
#define MAX31865_SCLK             GPIO_Pin_9
#define MAX31865_SDI              GPIO_Pin_11
#define MAX31865_DRDY 	          GPIO_Pin_13 

#define MAX31865_CS_SET           GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_CS,Bit_SET)
#define MAX31865_CS_CLR      		  GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_CS,Bit_RESET)
#define MAX31865_SCLK_SET    			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SCLK,Bit_SET)
#define MAX31865_SCLK_CLR    			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SCLK,Bit_RESET)
#define MAX31865_SDI_SET    			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SDI,Bit_SET)
#define MAX31865_SDI_CLR     			GPIO_WriteBit(MAX31865_CONTROL_PORT,MAX31865_SDI,Bit_RESET)

#define MAX31865_SDO_READ    			GPIO_ReadInputDataBit(MAX31865_CONTROL_PORT,MAX31865_SDO)
#define MAX31865_DRDY_READ   			GPIO_ReadInputDataBit(MAX31865_CONTROL_PORT,MAX31865_DRDY)

void MAX31865_Init(void); //MAX31865 初始化,软件模拟
void MAX31865_Cfg(void);  //MAX31865 配置
float MAX31865_GetTemp(void);//MAX31865 获取温度

#endif

主函数显示?

/***********************************************
调用方式：无
返回值：
函数说明：主函数
************************************************/
int main(void)
{
	Bsp_init();//初始化板载程序
	while(1)
	{	
		Get_RTCSencod();
		//float temp = MAX31865_GetTemp();//软件模拟spi读取max31865合成温度
		float temp = Get_Hardware_SPI_Temp();//硬件spi读取max31865合成温度
		if(isReadTemp == 1 && isShowShell == 1){
		#if 0
		if(SysRTC_Secondflag == 1){
			SysRTC_Secondflag = 0;
			printf("%02d:%02d:%02d",THH, TMM, TSS);	
			printf("temp=%.2f\r\n",temp);
			LED_Light();
		#endif
		#if 1
		if(SysRTC_Secondflag == 1){
			SysRTC_Secondflag = 0;
			printf("%02d:%02d:%02d",THH, TMM, TSS);
			
			printf("temp=%.2f\r\n",temp);
			LED_Light();
			//delay_ms(100);
			}
		#endif
		}
	}

}

硬件模块连接示意图：?

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