STM32配置读取BMP280气压传感器数据

STM32配置读取BMP280气压传感器数据

BMP280是在BMP180基础上增强的绝对气压传感器，在飞控领域的高度识别方面应用也比较多。

BMP280和BMP180的区别：

市面上也有一些模块：

这里介绍STM32芯片和BMP280的连接和数据读取。

电路连接

BMP280和STM32的供电范围一致，可以在1.8V， 2.5V和3.3V多个供电电压点直接连接。

BMP280和STM32可以通过SPI或者I2C总线实现访问连接，I2C接口连接管脚少，这里采用I2C接口实现连接。

这里采用GPIO模拟I2C协议的方式，所以随意找2个管脚作为SCL和SDA。

用I2C总线连接时，BMP280的SDO管脚的电平状态用作I2C地址低位的选择。

运行过程

运行过程包括测试参数的配置选择：

也包括循环运行过程的节奏控制：

这里以STM32F401CCU6和STM32CUBEIDE开发环境为例，实现BMP280的访问读取数据，采用USB虚拟串口或普通串口方式打印输出。

初始化主要配置的寄存器0xF4 "ctrl_meas"的定义如下：




过采样率oversampling会对采样分辨率和噪声产生影响：




不同场景有推荐配置：

初始化主要配置的寄存器0xF5 "config"的定义如下：

测量时间和上面的测量间隔，就构成了数据输出率：


滤波参数和推荐：

按照数据手册表达方式，应该是：

STM32工程配置

首先建立基本工程并配置时钟系统：

配置USB虚拟串口：





配置USART1作为通讯串口：


配置两个管脚作为与BMP280的通讯管脚：

保存并生成初始工程代码：

STM32工程代码

I2C模拟时序用到的微秒延时函数，参考： STM32 HAL us delay（微秒延时）的指令延时实现方式及优化
USB虚拟串口的实现，参考： STM32 USB VCOM和HID的区别，配置及Echo功能实现（HAL）
STM32串口打印的实现，参考： STM32 UART串口printf函数应用及浮点打印代码空间节省 (HAL)
采用减少代码编译size的方式，参考： STM32 region `FLASH‘ overflowed by xxx bytes 问题解决

代码逻辑识别USB虚拟串口是否连接，如果连接，则通过USB虚拟串口打印输出，否则通过普通串口打印输出。
上电或重启后，STM32对BMP280进行初始化，如果失败，则打印输出报错信息，如果成功，则循环进行检测和输出压力，高度和温度值。

建立BMP280.h放置一些寄存器访问地址参数：

#ifndef __BMP280_H
#define __BMP280_H#include "main.h"
#include "math.h"
#include "string.h"
#include "stdio.h"
/**  BMP280 register address*/
#define BMP280_REGISTER_DIG_T1      0x88
#define BMP280_REGISTER_DIG_T2      0x8A
#define BMP280_REGISTER_DIG_T3      0x8C#define BMP280_REGISTER_DIG_P1      0x8E
#define BMP280_REGISTER_DIG_P2      0x90
#define BMP280_REGISTER_DIG_P3      0x92
#define BMP280_REGISTER_DIG_P4      0x94
#define BMP280_REGISTER_DIG_P5      0x96
#define BMP280_REGISTER_DIG_P6      0x98
#define BMP280_REGISTER_DIG_P7      0x9A
#define BMP280_REGISTER_DIG_P8      0x9C
#define BMP280_REGISTER_DIG_P9      0x9E#define BMP280_REGISTER_CHIPID      0xD0
#define BMP280_REGISTER_VERSION     0xD1
#define BMP280_REGISTER_SOFTRESET   0xE0
#define BMP280_REGISTER_STATUS      0xF3
#define BMP280_REGISTER_CONTROL     0xF4
#define BMP280_REGISTER_CONFIG      0xF5#define BMP280_TEMP_XLSB_REG        0xFC	    /*Temperature XLSB Register */
#define BMP280_TEMP_LSB_REG         0xFB        /*Temperature LSB Register  */
#define BMP280_TEMP_MSB_REG         0xFA        /*Temperature LSB Register  */
#define BMP280_PRESS_XLSB_REG       0xF9		/*Pressure XLSB  Register   */
#define BMP280_PRESS_LSB_REG        0xF8		/*Pressure LSB Register     */
#define BMP280_PRESS_MSB_REG        0xF7		/*Pressure MSB Register     *//*calibration parameters */
#define BMP280_DIG_T1_LSB_REG                0x88
#define BMP280_DIG_T1_MSB_REG                0x89
#define BMP280_DIG_T2_LSB_REG                0x8A
#define BMP280_DIG_T2_MSB_REG                0x8B
#define BMP280_DIG_T3_LSB_REG                0x8C
#define BMP280_DIG_T3_MSB_REG                0x8D
#define BMP280_DIG_P1_LSB_REG                0x8E
#define BMP280_DIG_P1_MSB_REG                0x8F
#define BMP280_DIG_P2_LSB_REG                0x90
#define BMP280_DIG_P2_MSB_REG                0x91
#define BMP280_DIG_P3_LSB_REG                0x92
#define BMP280_DIG_P3_MSB_REG                0x93
#define BMP280_DIG_P4_LSB_REG                0x94
#define BMP280_DIG_P4_MSB_REG                0x95
#define BMP280_DIG_P5_LSB_REG                0x96
#define BMP280_DIG_P5_MSB_REG                0x97
#define BMP280_DIG_P6_LSB_REG                0x98
#define BMP280_DIG_P6_MSB_REG                0x99
#define BMP280_DIG_P7_LSB_REG                0x9A
#define BMP280_DIG_P7_MSB_REG                0x9B
#define BMP280_DIG_P8_LSB_REG                0x9C
#define BMP280_DIG_P8_MSB_REG                0x9D
#define BMP280_DIG_P9_LSB_REG                0x9E
#define BMP280_DIG_P9_MSB_REG                0x9Ftypedef struct {uint16_t T1; 		/*<calibration T1 data*/int16_t T2;  	 	/*<calibration T2 data*/int16_t T3;  		/*<calibration T3 data*/uint16_t P1;  	    /*<calibration P1 data*/int16_t P2;  		/*<calibration P2 data*/int16_t P3;  		/*<calibration P3 data*/int16_t P4;  		/*<calibration P4 data*/int16_t P5;  		/*<calibration P5 data*/int16_t P6;  		/*<calibration P6 data*/int16_t P7;  		/*<calibration P7 data*/int16_t P8;  		/*<calibration P8 data*/int16_t P9;			/*<calibration P9 data*/int32_t T_fine;	/*<calibration t_fine data*/
} BMP280_HandleTypeDef;typedef struct
{uint8_t Index;int32_t AvgBuffer[8];
} BMP280_AvgTypeDef;#define MSLP     101325          // Mean Sea Level Pressure = 1013.25 hPA (1hPa = 100Pa = 1mbar)
#define ALTITUDE_OFFSET          10000void I2C_Init(void);
void BMP280_Init();
void BMP280_CalTemperatureAndPressureAndAltitude(int32_t *temperature, int32_t *pressure, int32_t *Altitude);#endif /* __BMP280_H */其中ALTITUDE_OFFSET用于设定用户高度偏差。

建立BMP280.c实现访问和计算函数：

#include "BMP280.h"extern void PY_Delay_us_t(uint32_t Delay);
extern char console[128];//BMP280 I2C access protocol
#define us_num 2#define SCL_OUT_H HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_SET)
#define SCL_OUT_L HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12, GPIO_PIN_RESET)
#define SDA_OUT_H HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, GPIO_PIN_SET)
#define SDA_OUT_L HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, GPIO_PIN_RESET)
#define SDA_IN HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_13)void I2C_Init(void)
{SCL_OUT_H;SDA_OUT_H;PY_Delay_us_t(100000);}void I2C_Start(void)
{PY_Delay_us_t(us_num) ;SDA_OUT_H;SCL_OUT_H;PY_Delay_us_t(us_num/2) ;SDA_OUT_L;PY_Delay_us_t(us_num/2) ;SCL_OUT_L;
}void I2C_Stop(void)
{SCL_OUT_L;PY_Delay_us_t(us_num) ;SDA_OUT_L;PY_Delay_us_t(us_num) ;SCL_OUT_H;PY_Delay_us_t(us_num) ;SDA_OUT_H;PY_Delay_us_t(us_num) ;
}void I2C_Write_Ack(void)
{PY_Delay_us_t(us_num/2) ;SDA_OUT_L;PY_Delay_us_t(us_num/2) ;SCL_OUT_H;PY_Delay_us_t(us_num) ;SCL_OUT_L;SDA_OUT_H;}uint8_t I2C_Read_Ack(void)
{uint8_t status=0;SCL_OUT_L;PY_Delay_us_t(us_num/2) ;SDA_OUT_H;PY_Delay_us_t(us_num/2) ;status = SDA_IN;SCL_OUT_H;PY_Delay_us_t(us_num) ;SCL_OUT_L;SDA_OUT_L;return status;}void I2C_Send_Byte(uint8_t txd){for(uint8_t i=0;i<8;i++){PY_Delay_us_t(us_num/2) ;if((txd&0x80)>>7) SDA_OUT_H;else SDA_OUT_L;txd<<=1;PY_Delay_us_t(us_num/2) ;SCL_OUT_H;PY_Delay_us_t(us_num) ;SCL_OUT_L;}SDA_OUT_L;
}uint8_t I2C_Read_Byte(unsigned char rdack)
{uint8_t rxd=0;for(uint8_t i=0;i<8;i++ ){SCL_OUT_L;PY_Delay_us_t(us_num/2) ;SDA_OUT_H;PY_Delay_us_t(us_num/2) ;SCL_OUT_H;rxd<<=1;if(SDA_IN) rxd++;PY_Delay_us_t(us_num) ;}SCL_OUT_L;SDA_OUT_H;if (rdack) I2C_Write_Ack();return rxd;
}#define BMP280_I2C_ADDR_SEL 1BMP280_HandleTypeDef bmp280;
#define dig_T1 bmp280.T1
#define dig_T2 bmp280.T2
#define dig_T3 bmp280.T3
#define dig_P1 bmp280.P1
#define dig_P2 bmp280.P2
#define dig_P3 bmp280.P3
#define dig_P4 bmp280.P4
#define dig_P5 bmp280.P5
#define dig_P6 bmp280.P6
#define dig_P7 bmp280.P7
#define dig_P8 bmp280.P8
#define dig_P9 bmp280.P9
#define t_fine bmp280.T_fineint32_t gs32Pressure0 = MSLP;void BMP280_WriteReg(uint8_t WrAddr, uint8_t data)
{uint8_t daddr; //device address (0x1e<<1)if(BMP280_I2C_ADDR_SEL==0) daddr = 0xec; //device address for SDO low status (0x76<<1)else daddr = 0xee; //device address for SDO high status (0x77<<1)I2C_Start();I2C_Send_Byte(daddr);I2C_Read_Ack();I2C_Send_Byte(WrAddr);I2C_Read_Ack();I2C_Send_Byte(data);I2C_Read_Ack();I2C_Stop();}uint8_t BMP280_ReadReg(uint8_t RdAddr)
{uint8_t RegValue = 0;uint8_t daddr;if(BMP280_I2C_ADDR_SEL==0) daddr = 0xec; //device address for SDO low status (0x76<<1)else daddr = 0xee; //device address for SDO high status (0x77<<1)I2C_Start();I2C_Send_Byte(daddr);I2C_Read_Ack();I2C_Send_Byte(RdAddr);I2C_Read_Ack();I2C_Start();I2C_Send_Byte(daddr+1);I2C_Read_Ack();RegValue=I2C_Read_Byte(0);I2C_Stop();return RegValue;
}/* Returns temperature in DegC, double precision. Output value of "1.23"equals 51.23 DegC. */
double BMP280_Compensate_Temperature(int32_t adc_T)
{double var1, var2, temperature;var1 = (((double) adc_T) / 16384.0 - ((double) dig_T1) / 1024.0) * ((double) dig_T2);var2 = ((((double) adc_T) / 131072.0 - ((double) dig_T1) / 8192.0)  * (((double) adc_T) / 131072.0- ((double) dig_T1) / 8192.0)) * ((double) dig_T3);t_fine = (int32_t) (var1 + var2);temperature = (var1 + var2) / 5120.0;return temperature;
}/* Returns pressure in Pa as double. Output value of "6386.2"equals 96386.2 Pa = 963.862 hPa */
double BMP280_Compensate_Pressure(int32_t adc_P)
{double var1, var2, pressure;var1 = ((double)t_fine / 2.0) - 64000.0;var2 = var1 * var1 * ((double) dig_P6) / 32768.0;var2 = var2 + var1 * ((double) dig_P5) * 2.0;var2 = (var2 / 4.0) + (((double) dig_P4) * 65536.0);var1 = (((double) dig_P3) * var1 * var1 / 524288.0  + ((double) dig_P2) * var1) / 524288.0;var1 = (1.0 + var1 / 32768.0) * ((double) dig_P1);if (var1 == 0.0) {return 0; // avoid exception caused by division by zero}pressure = 1048576.0 - (double) adc_P;pressure = (pressure - (var2 / 4096.0)) * 6250.0 / var1;var1 = ((double) dig_P9) * pressure * pressure / 2147483648.0;var2 = pressure * ((double) dig_P8) / 32768.0;pressure = pressure + (var1 + var2 + ((double) dig_P7)) / 16.0;return pressure;
}double BMP280_Get_Pressure(void)
{uint8_t lsb, msb, xlsb;int32_t adc_P;xlsb = BMP280_ReadReg(BMP280_PRESS_XLSB_REG);lsb = BMP280_ReadReg(BMP280_PRESS_LSB_REG);msb = BMP280_ReadReg(BMP280_PRESS_MSB_REG);adc_P = (msb << 12) | (lsb << 4) | (xlsb >> 4);//adc_P = 51988;return BMP280_Compensate_Pressure(adc_P);
}void BMP280_Get_Temperature_And_Pressure(double *temperature, double *pressure)
{uint8_t lsb, msb, xlsb;int32_t adc_P,adc_T;xlsb = BMP280_ReadReg(BMP280_TEMP_XLSB_REG);lsb = BMP280_ReadReg(BMP280_TEMP_LSB_REG);msb = BMP280_ReadReg(BMP280_TEMP_MSB_REG);adc_T = (msb << 12) | (lsb << 4) | (xlsb >> 4);//adc_T = 415148;* temperature = BMP280_Compensate_Temperature(adc_T);xlsb = BMP280_ReadReg(BMP280_PRESS_XLSB_REG);lsb = BMP280_ReadReg(BMP280_PRESS_LSB_REG);msb = BMP280_ReadReg(BMP280_PRESS_MSB_REG);adc_P = (msb << 12) | (lsb << 4) | (xlsb >> 4);//adc_P = 51988;* pressure = BMP280_Compensate_Pressure(adc_P);
}#define BMP280_AVG_TIMES 8 //maximum: 8
void BMP280_CalAvgValue(uint8_t *pIndex, int32_t *pAvgBuffer, int32_t InVal, int32_t *pOutVal)
{uint8_t i;static uint8_t status = 0;*(pAvgBuffer + ((*pIndex) ++)) = InVal;*pIndex %= BMP280_AVG_TIMES;if(status<=24) //skip average computation before getting pre-defined data times (24 times){*pOutVal = InVal;status++;}else //compute average value{*pOutVal = 0;for(i = 0; i < BMP280_AVG_TIMES; i ++){*pOutVal += *(pAvgBuffer + i);}*pOutVal /= BMP280_AVG_TIMES;}
}void BMP280_CalculateAbsoluteAltitude(int32_t *pAltitude, int32_t PressureVal)
{*pAltitude = 4433000 * (1 - pow((PressureVal / (float)gs32Pressure0), 0.1903));
}void BMP280_CalTemperatureAndPressureAndAltitude(int32_t *temperature, int32_t *pressure, int32_t *Altitude)
{double CurPressure, CurTemperature;int32_t CurAltitude;static BMP280_AvgTypeDef BMP280_Filter[3];BMP280_Get_Temperature_And_Pressure(&CurTemperature, &CurPressure);BMP280_CalAvgValue(&BMP280_Filter[0].Index, BMP280_Filter[0].AvgBuffer, (int32_t)(CurPressure), pressure);BMP280_CalculateAbsoluteAltitude(&CurAltitude, (*pressure));BMP280_CalAvgValue(&BMP280_Filter[1].Index, BMP280_Filter[1].AvgBuffer, CurAltitude, Altitude);BMP280_CalAvgValue(&BMP280_Filter[2].Index, BMP280_Filter[2].AvgBuffer, (int32_t)CurTemperature*10, temperature);(*Altitude) += ALTITUDE_OFFSET;return;
}void BMP280_Read_Calibration(void)
{uint8_t lsb, msb;/* read the temperature calibration parameters */lsb = BMP280_ReadReg(BMP280_DIG_T1_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_T1_MSB_REG);dig_T1 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_T2_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_T2_MSB_REG);dig_T2 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_T3_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_T3_MSB_REG);dig_T3 = msb << 8 | lsb;/* read the pressure calibration parameters */lsb = BMP280_ReadReg(BMP280_DIG_P1_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P1_MSB_REG);dig_P1 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P2_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P2_MSB_REG);dig_P2 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P3_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P3_MSB_REG);dig_P3 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P4_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P4_MSB_REG);dig_P4 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P5_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P5_MSB_REG);dig_P5 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P6_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P6_MSB_REG);dig_P6 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P7_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P7_MSB_REG);dig_P7 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P8_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P8_MSB_REG);dig_P8 = msb << 8 | lsb;lsb = BMP280_ReadReg(BMP280_DIG_P9_LSB_REG);msb = BMP280_ReadReg(BMP280_DIG_P9_MSB_REG);dig_P9 = msb << 8 | lsb;}void BMP280_Init()
{uint8_t u8ChipID, u8CtrlMod, u8Status;u8ChipID = BMP280_ReadReg(BMP280_REGISTER_CHIPID);u8CtrlMod = BMP280_ReadReg(BMP280_REGISTER_CONTROL);u8Status = BMP280_ReadReg(BMP280_REGISTER_STATUS);if(u8ChipID == 0x58){if(USB_CONN_STATUS()){sprintf(console, "\r\nBMP280 initial successful : ChipID [0x%x] CtrlMod [0x%x] Status [0x%x] \r\n", u8ChipID,u8CtrlMod,u8Status);CDC_Transmit_FS((uint8_t*)console, strlen(console));}else{printf("\r\nBMP280 initial successful : ChipID [0x%x] CtrlMod [0x%x] Status [0x%x] \r\n", u8ChipID,u8CtrlMod,u8Status);}BMP280_WriteReg(BMP280_REGISTER_CONTROL, 0xFF); //ctrl_meas registerBMP280_WriteReg(BMP280_REGISTER_CONFIG, 0x0C);  //config registerBMP280_Read_Calibration();}else{if(USB_CONN_STATUS()){sprintf(console, "\r\nBMP280 initial failure : ChipID [0x%x] CtrlMod [0x%x] Status [0x%x] \r\n", u8ChipID,u8CtrlMod,u8Status);CDC_Transmit_FS((uint8_t*)console, strlen(console));}else{printf("\r\nBMP280 initial failure : ChipID [0x%x] CtrlMod [0x%x] Status [0x%x] \r\n", u8ChipID,u8CtrlMod,u8Status);}return BMP280_Init();}}

main.c文件的实现功能测试代码，注意这里把BMP280管脚SDO拉到了高电平，所以定义为#define BMP280_I2C_ADDR_SEL 1：

/* USER CODE BEGIN Header */
/********************************************************************************* @file           : main.c* @brief          : Main program body******************************************************************************* @attention** Copyright (c) 2023 STMicroelectronics.* All rights reserved.** This software is licensed under terms that can be found in the LICENSE file* in the root directory of this software component.* If no LICENSE file comes with this software, it is provided AS-IS.********************************************************************************/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usb_device.h"/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "BMP280.h"
#include "usart.h"/* USER CODE END Includes *//* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
__IO float usDelayBase;
void PY_usDelayTest(void)
{__IO uint32_t firstms, secondms;__IO uint32_t counter = 0;firstms = HAL_GetTick()+1;secondms = firstms+1;while(uwTick!=firstms) ;while(uwTick!=secondms) counter++;usDelayBase = ((float)counter)/1000;
}void PY_Delay_us_t(uint32_t Delay)
{__IO uint32_t delayReg;__IO uint32_t usNum = (uint32_t)(Delay*usDelayBase);delayReg = 0;while(delayReg!=usNum) delayReg++;
}void PY_usDelayOptimize(void)
{__IO uint32_t firstms, secondms;__IO float coe = 1.0;firstms = HAL_GetTick();PY_Delay_us_t(1000000) ;secondms = HAL_GetTick();coe = ((float)1000)/(secondms-firstms);usDelayBase = coe*usDelayBase;
}void PY_Delay_us(uint32_t Delay)
{__IO uint32_t delayReg;__IO uint32_t msNum = Delay/1000;__IO uint32_t usNum = (uint32_t)((Delay%1000)*usDelayBase);if(msNum>0) HAL_Delay(msNum);delayReg = 0;while(delayReg!=usNum) delayReg++;
}
/* USER CODE END PTD *//* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD *//* USER CODE END PD *//* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM *//* USER CODE END PM *//* Private variables ---------------------------------------------------------*/
UART_HandleTypeDef huart1;/* USER CODE BEGIN PV *//* USER CODE END PV *//* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART1_UART_Init(void);
/* USER CODE BEGIN PFP *//* USER CODE END PFP *//* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
int32_t PressureVal = 0, TemperatureVal = 0, AltitudeVal = 0;
char mychar[100];
char console[128];
/*
*Convert float to string type
*Written by Pegasus Yu in 2022
*stra: string address as mychar from char mychar[];
*float: float input like 12.345
*flen: fraction length as 3 for 12.345
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
void py_f2s4printf(char * stra, float x, uint8_t flen)
{uint32_t base;int64_t dn;char mc[32];base = pow(10,flen);dn = x*base;sprintf(stra, "%d.", (int)(dn/base));dn = abs(dn);if(dn%base==0){for(uint8_t j=1;j<=flen;j++){stra = strcat(stra, "0");}return;}else{if(flen==1){sprintf(mc, "%d", (int)(dn%base));stra = strcat(stra, mc);return;}for(uint8_t j=1;j<flen;j++){if((dn%base)<pow(10,j)){for(uint8_t k=1;k<=(flen-j);k++){stra = strcat(stra, "0");}sprintf(mc, "%d", (int)(dn%base));stra = strcat(stra, mc);return;}}sprintf(mc, "%d", (int)(dn%base));stra = strcat(stra, mc);return;}
}
/* USER CODE END 0 *//*** @brief  The application entry point.* @retval int*/
int main(void)
{/* USER CODE BEGIN 1 *//* USER CODE END 1 *//* MCU Configuration--------------------------------------------------------*//* Reset of all peripherals, Initializes the Flash interface and the Systick. */HAL_Init();/* USER CODE BEGIN Init *//* USER CODE END Init *//* Configure the system clock */SystemClock_Config();/* USER CODE BEGIN SysInit *//* USER CODE END SysInit *//* Initialize all configured peripherals */MX_GPIO_Init();MX_USB_DEVICE_Init();MX_USART1_UART_Init();/* USER CODE BEGIN 2 */PY_usDelayTest();PY_usDelayOptimize();I2C_Init();BMP280_Init();PY_Delay_us_t(100000); //Waiting for the stability of BMP280 after initiation/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){BMP280_CalTemperatureAndPressureAndAltitude(&TemperatureVal, &PressureVal, &AltitudeVal);if(USB_CONN_STATUS()){sprintf(console, "\r\n\r\n--------------BMP280 TEST---------------");while( CDC_Transmit_FS((uint8_t*)console, strlen(console)) == USBD_BUSY ) PY_Delay_us_t(1);py_f2s4printf(mychar, (float)PressureVal/100, 2);sprintf(console, "\r\n Pressure: %s\r\n", mychar);while( CDC_Transmit_FS((uint8_t*)console, strlen(console)) == USBD_BUSY ) PY_Delay_us_t(1);py_f2s4printf(mychar, (float)AltitudeVal/100, 2);sprintf(console, "\r\n Altitude: %s\r\n", mychar);while( CDC_Transmit_FS((uint8_t*)console, strlen(console)) == USBD_BUSY ) PY_Delay_us_t(1);py_f2s4printf(mychar, (float)TemperatureVal/10, 1);sprintf(console, "\r\n Temperature: %s\r\n", mychar);while( CDC_Transmit_FS((uint8_t*)console, strlen(console)) == USBD_BUSY ) PY_Delay_us_t(1);}else{printf("\r\n\r\n-----------------------------------------------");py_f2s4printf(mychar, (float)PressureVal/100, 2);printf("\r\n Pressure: %s\r\n", mychar);py_f2s4printf(mychar, (float)AltitudeVal/100, 2);sprintf(console, "\r\n Altitude: %s\r\n", mychar);printf("\r\n Altitude: %s\r\n", mychar);py_f2s4printf(mychar, (float)TemperatureVal/10, 1);sprintf(console, "\r\n Temperature: %s\r\n", mychar);}PY_Delay_us_t(200000);/* USER CODE END WHILE *//* USER CODE BEGIN 3 */}/* USER CODE END 3 */
}/*** @brief System Clock Configuration* @retval None*/
void SystemClock_Config(void)
{RCC_OscInitTypeDef RCC_OscInitStruct = {0};RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};/** Configure the main internal regulator output voltage*/__HAL_RCC_PWR_CLK_ENABLE();__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState = RCC_HSE_ON;RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLM = 25;RCC_OscInitStruct.PLL.PLLN = 336;RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;RCC_OscInitStruct.PLL.PLLQ = 7;if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK){Error_Handler();}/** Initializes the CPU, AHB and APB buses clocks*/RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK){Error_Handler();}
}/*** @brief USART1 Initialization Function* @param None* @retval None*/
static void MX_USART1_UART_Init(void)
{/* USER CODE BEGIN USART1_Init 0 *//* USER CODE END USART1_Init 0 *//* USER CODE BEGIN USART1_Init 1 *//* USER CODE END USART1_Init 1 */huart1.Instance = USART1;huart1.Init.BaudRate = 115200;huart1.Init.WordLength = UART_WORDLENGTH_8B;huart1.Init.StopBits = UART_STOPBITS_1;huart1.Init.Parity = UART_PARITY_NONE;huart1.Init.Mode = UART_MODE_TX_RX;huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;huart1.Init.OverSampling = UART_OVERSAMPLING_16;if (HAL_UART_Init(&huart1) != HAL_OK){Error_Handler();}/* USER CODE BEGIN USART1_Init 2 *//* USER CODE END USART1_Init 2 */}/*** @brief GPIO Initialization Function* @param None* @retval None*/
static void MX_GPIO_Init(void)
{GPIO_InitTypeDef GPIO_InitStruct = {0};/* GPIO Ports Clock Enable */__HAL_RCC_GPIOH_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();__HAL_RCC_GPIOA_CLK_ENABLE();/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOB, GPIO_PIN_12|GPIO_PIN_13, GPIO_PIN_SET);/*Configure GPIO pins : PB12 PB13 */GPIO_InitStruct.Pin = GPIO_PIN_12|GPIO_PIN_13;GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_OD;GPIO_InitStruct.Pull = GPIO_PULLUP;GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);}/* USER CODE BEGIN 4 *//* USER CODE END 4 *//*** @brief  This function is executed in case of error occurrence.* @retval None*/
void Error_Handler(void)
{/* USER CODE BEGIN Error_Handler_Debug *//* User can add his own implementation to report the HAL error return state */__disable_irq();while (1){}/* USER CODE END Error_Handler_Debug */
}#ifdef  USE_FULL_ASSERT
/*** @brief  Reports the name of the source file and the source line number*         where the assert_param error has occurred.* @param  file: pointer to the source file name* @param  line: assert_param error line source number* @retval None*/
void assert_failed(uint8_t *file, uint32_t line)
{/* USER CODE BEGIN 6 *//* User can add his own implementation to report the file name and line number,ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) *//* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */

注意芯片内部已经配置选用了滤波功能，采用滤波功能后的输出速率不高，对于外部进行静态高度测量，可以再进行取多次平均的算法，如果是运动过程高度测量，则不必再采用平均算法。另外，可以给

测试输出

代码运行的测试输出：

工程代码下载

STM32F401CCU6配置读取BMP280工程下载

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