MAX6675+STM32与51单片机用K型热电偶的温度控制源码与资料下载 -

/*********************************************************************************
* 文件名：main.c
* 描述：通过stm32的spi1读取max6675的温度值，并通过uart1发送出来
*
* 实验平台：STM32开发板
* 库版本：ST3.0.0
* 硬件连接： ------------------------------------
* |PA6-SPI1-MISO：MAX6675-SO |
* |PA7-SPI1-MOSI：MAX6675-SI |
* |PA5-SPI1-SCK ：MAX6675-SCK |
* |PA4-SPI1-NSS ：MAX6675-CS |
* ------------------------------------
**********************************************************************************/
#include "stm32f10x.h"
#include "usart1.h"
#define MAX6675_CS GPIO_Pin_4
#define MAX6675_CSL() GPIOA->BRR = MAX6675_CS;
#define MAX6675_CSH() GPIOA->BSRR = MAX6675_CS;
/*
* 函数名：SPI1_Init
* 描述 MAX6675 接口初始化
* 输入：无
* 输出：无
* 返回：无
*/
void SPI_MAX6675_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
SPI_InitTypeDef SPI_InitStructure;
/* 使能 SPI1 时钟 */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_SPI1, ENABLE);
/* ---------通信I/O初始化----------------
* PA5-SPI1-SCK :MAX6675_SCK
* PA6-SPI1-MISO:MAX6675_SO
* PA7-SPI1-MOSI:MAX6675_SI
*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; // 复用输出
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* ---------控制I/O初始化----------------*/
/* PA4-SPI1-NSS:MAX6675_CS */ // 片选
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // 推免输出
GPIO_Init(GPIOA, &GPIO_InitStructure);
GPIO_SetBits(GPIOA, GPIO_Pin_4); // 先把片选拉高，真正用的时候再拉低
/* SPI1 配置 */
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_Low;
SPI_InitStructure.SPI_CPHA = SPI_CPHA_1Edge;
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_Init(SPI1, &SPI_InitStructure);
/* 使能 SPI1 */
SPI_Cmd(SPI1, ENABLE);
}
/*
*
*
*
*/
unsigned char MAX6675_ReadByte(void)
{
/* Loop while DR register in not emplty */
while(SPI_I2S_GetFlagStatus(SPI1,SPI_I2S_FLAG_TXE) == RESET);
/* Send byte through the SPI1 peripheral */
SPI_I2S_SendData(SPI1, 0xff);
/* Wait to receive a byte */
while(SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
/* Return the byte read from the SPI bus */
return SPI_I2S_ReceiveData(SPI1);
}
/*
* 函数名：main
* 描述：主函数
* 输入：无
* 输出：无
*/
main (void)
{
unsigned int t,i;
unsigned char c;
unsigned char flag;
float temprature;
/* 配置系统时钟为72M */
SystemInit();
/* MAX6675 SPI 接口初始化 */
SPI_MAX6675_Init();
USART1_Config();
while(1)
{
MAX6675_CSL();
c = MAX6675_ReadByte();
i = c;
i = i<<8;
c = MAX6675_ReadByte();
MAX6675_CSH();
i = i|((unsigned int)c); //i是读出来的原始数据
flag = i&0x04; //flag保存了热电偶的连接状态
t = i<<1;
t = t>>4;
temprature = t*0.25;
if(i!=0) //max6675有数据返回
{
if(flag==0) //热电偶已连接
{
printf("原始数据是：%04X, 当前温度是：%4.2f。\r\n",i,temprature);
}
else //热电偶掉线
{
printf("未检测到热电偶，请检查。\r\n");
}
}
else //max6675没有数据返回
{
printf("max6675没有数据返回，请检查max6675连接。\r\n");
}
for(i=0;i<0x2fffff;i++); //max6675的转换时间是0.2秒左右，所以两次转换间隔不要太近
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…………限于本文篇幅余下代码请从51黑下载附件…………

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