32单片机max31855的程序
时间: 2023-08-08 16:07:58 浏览: 73
以下是一个简单的基于32单片机的MAX31855程序,可以读取热电偶温度传感器数据:
```c
#include <stdio.h>
#include <stdlib.h>
#include "stm32f4xx.h"
#include "stm32f4xx_gpio.h"
#include "stm32f4xx_rcc.h"
#include "stm32f4xx_spi.h"
#define CS_PIN GPIO_Pin_0
#define CS_PORT GPIOA
SPI_InitTypeDef SPI_InitStruct;
GPIO_InitTypeDef GPIO_InitStruct;
void delay_ms(uint32_t ms) {
uint32_t i, j;
for (i = 0; i < ms; i++) {
for (j = 0; j < 20000; j++);
}
}
void spi_init(void) {
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1, ENABLE);
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStruct.GPIO_OType = GPIO_OType_PP;
GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStruct.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_InitStruct.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_Init(GPIOA, &GPIO_InitStruct);
GPIO_InitStruct.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStruct.GPIO_Pin = CS_PIN;
GPIO_Init(CS_PORT, &GPIO_InitStruct);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource5, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource6, GPIO_AF_SPI1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource7, GPIO_AF_SPI1);
SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
SPI_InitStruct.SPI_DataSize = SPI_DataSize_16b;
SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;
SPI_InitStruct.SPI_Mode = SPI_Mode_Master;
SPI_InitStruct.SPI_NSS = SPI_NSS_Soft;
SPI_InitStruct.SPI_CPOL = SPI_CPOL_High;
SPI_InitStruct.SPI_CPHA = SPI_CPHA_2Edge;
SPI_Init(SPI1, &SPI_InitStruct);
SPI_Cmd(SPI1, ENABLE);
}
uint16_t spi_transfer(uint16_t data) {
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_TXE) == RESET);
SPI_I2S_SendData(SPI1, data);
while (SPI_I2S_GetFlagStatus(SPI1, SPI_I2S_FLAG_RXNE) == RESET);
return SPI_I2S_ReceiveData(SPI1);
}
uint16_t max31855_read(void) {
uint16_t data = 0;
GPIO_ResetBits(CS_PORT, CS_PIN);
data = spi_transfer(0x0000);
data = spi_transfer(0x0000);
GPIO_SetBits(CS_PORT, CS_PIN);
return data;
}
int main(void) {
uint16_t data = 0;
float temp;
spi_init();
while (1) {
data = max31855_read();
temp = (data >> 2) * 0.25;
printf("Temperature: %.2f\n", temp);
delay_ms(1000);
}
}
```
这个程序初始化了SPI接口,并使用GPIO控制CS引脚。它通过spi_transfer函数来进行数据传输。在main函数中,它不断读取MAX31855的数据并将其转换为温度值。