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发表于 2022-1-17 15:22:02
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#include <math.h>
#include "stdbool.h"
#include "delay.h"
#include "myiic.h"
#include "bmp280.h"
#include "usart.h"
#define BMP280_PRESSURE_OSR (BMP280_OVERSAMP_8X)
#define BMP280_TEMPERATURE_OSR (BMP280_OVERSAMP_16X)
#define BMP280_MODE (BMP280_PRESSURE_OSR << 2 | BMP280_TEMPERATURE_OSR << 5 | BMP280_NORMAL_MODE)
typedef struct
{
u16 dig_T1;/* calibration T1 data */
s16 dig_T2; /* calibration T2 data */
s16 dig_T3; /* calibration T3 data */
u16 dig_P1;/* calibration P1 data */
s16 dig_P2; /* calibration P2 data */
s16 dig_P3; /* calibration P3 data */
s16 dig_P4; /* calibration P4 data */
s16 dig_P5; /* calibration P5 data */
s16 dig_P6; /* calibration P6 data */
s16 dig_P7; /* calibration P7 data */
s16 dig_P8; /* calibration P8 data */
s16 dig_P9; /* calibration P9 data */
s32 t_fine; /* calibration t_fine data */
} bmp280Calib;
bmp280Calib bmp280Cal;
static u8 bmp280ID = 0;
static bool isInit = false;
static s32 bmp280RawPressure = 0;
static s32 bmp280RawTemperature = 0;
static void bmp280GetPressure(void);
static void presssureFilter(float* in, float* out);
static float bmp280PressureToAltitude(float* pressure/*, float* groundPressure, float* groundTemp*/);
bool bmp280Init(void)
{
if (isInit)
return true;
IIC_Init(); /*3õê¼»ˉI2C*/
delay_ms(20);
// iicDevWriteByte(BMP280_ADDR,BMP280_RST_REG,0xb6);
//
// delay_ms(20);
bmp280ID=iicDevReadByte(BMP280_ADDR,BMP280_CHIP_ID); /* ¶áè¡bmp280 ID*/
if(bmp280ID == BMP280_DEFAULT_CHIP_ID)
printf("BMP280 ID IS: 0x%X\n",bmp280ID);
else
return false;
/* ¶áè¡D￡×¼êy¾Y */
iicDevRead(BMP280_ADDR, BMP280_TEMPERATURE_CALIB_DIG_T1_LSB_REG, 24, (u8 *)&bmp280Cal);
iicDevWriteByte(BMP280_ADDR, BMP280_CTRL_MEAS_REG,BMP280_MODE);
iicDevWriteByte(BMP280_ADDR, BMP280_CONFIG_REG,5<<2); /*ÅäÖÃIIRÂË2¨*/
// printf("BMP280 Calibrate Registor Are: \r\n");
// for(i=0;i<24;i++)
// printf("Registor %2d: 0x%X\n",i,p[i]);
isInit = true;
return true;
}
static void bmp280GetPressure(void)
{
u8 data[BMP280_DATA_FRAME_SIZE];
// read data from sensor
iicDevRead(BMP280_ADDR, BMP280_PRESSURE_MSB_REG, BMP280_DATA_FRAME_SIZE, data);
bmp280RawPressure = (s32)((((uint32_t)(data[0])) << 12) | (((uint32_t)(data[1])) << 4) | ((uint32_t)data[2] >> 4));
bmp280RawTemperature = (s32)((((uint32_t)(data[3])) << 12) | (((uint32_t)(data[4])) << 4) | ((uint32_t)data[5] >> 4));
}
// Returns temperature in DegC, resolution is 0.01 DegC. Output value of "5123" equals 51.23 DegC
// t_fine carries fine temperature as global value
static s32 bmp280CompensateT(s32 adcT)
{
s32 var1, var2, T;
var1 = ((((adcT >> 3) - ((s32)bmp280Cal.dig_T1 << 1))) * ((s32)bmp280Cal.dig_T2)) >> 11;
var2 = (((((adcT >> 4) - ((s32)bmp280Cal.dig_T1)) * ((adcT >> 4) - ((s32)bmp280Cal.dig_T1))) >> 12) * ((s32)bmp280Cal.dig_T3)) >> 14;
bmp280Cal.t_fine = var1 + var2;
T = (bmp280Cal.t_fine * 5 + 128) >> 8;
return T;
}
// Returns pressure in Pa as unsigned 32 bit integer in Q24.8 format (24 integer bits and 8 fractional bits).
// Output value of "24674867" represents 24674867/256 = 96386.2 Pa = 963.862 hPa
static uint32_t bmp280CompensateP(s32 adcP)
{
int64_t var1, var2, p;
var1 = ((int64_t)bmp280Cal.t_fine) - 128000;
var2 = var1 * var1 * (int64_t)bmp280Cal.dig_P6;
var2 = var2 + ((var1*(int64_t)bmp280Cal.dig_P5) << 17);
var2 = var2 + (((int64_t)bmp280Cal.dig_P4) << 35);
var1 = ((var1 * var1 * (int64_t)bmp280Cal.dig_P3) >> 8) + ((var1 * (int64_t)bmp280Cal.dig_P2) << 12);
var1 = (((((int64_t)1) << 47) + var1)) * ((int64_t)bmp280Cal.dig_P1) >> 33;
if (var1 == 0)
return 0;
p = 1048576 - adcP;
p = (((p << 31) - var2) * 3125) / var1;
var1 = (((int64_t)bmp280Cal.dig_P9) * (p >> 13) * (p >> 13)) >> 25;
var2 = (((int64_t)bmp280Cal.dig_P8) * p) >> 19;
p = ((p + var1 + var2) >> 8) + (((int64_t)bmp280Cal.dig_P7) << 4);
return (uint32_t)p;
}
#define FILTER_NUM 5
#define FILTER_A 0.1f
/*ÏT·ùƽ¾ùÂË2¨·¨*/
static void presssureFilter(float* in, float* out)
{
static u8 i=0;
static float filter_buf[FILTER_NUM]={0.0};
double filter_sum=0.0;
u8 cnt=0;
float deta;
if(filter_buf[i] == 0.0f)
{
filter_buf[i]=*in;
*out=*in;
if(++i>=FILTER_NUM) i=0;
} else
{
if(i) deta=*in-filter_buf[i-1];
else deta=*in-filter_buf[FILTER_NUM-1];
if(fabs(deta)<FILTER_A)
{
filter_buf[i]=*in;
if(++i>=FILTER_NUM) i=0;
}
for(cnt=0;cnt<FILTER_NUM;cnt++)
{
filter_sum+=filter_buf[cnt];
}
*out=filter_sum /FILTER_NUM;
}
}
void bmp280GetData(float* pressure, float* temperature, float* asl)
{
static float t;
static float p;
bmp280GetPressure();
t = bmp280CompensateT(bmp280RawTemperature)/100.0;
p = bmp280CompensateP(bmp280RawPressure)/25600.0;
presssureFilter(&p,pressure);
*temperature = (float)t;/*μ￥λ¶è*/
// *pressure = (float)p ; /*μ￥λhPa*/
*asl=bmp280PressureToAltitude(pressure); /*×a»»3éo￡°Î*/
}
#define CONST_PF 0.1902630958 //(1/5.25588f) Pressure factor
#define FIX_TEMP 25 // Fixed Temperature. ASL is a function of pressure and temperature, but as the temperature changes so much (blow a little towards the flie and watch it drop 5 degrees) it corrupts the ASL estimates.
// TLDR: Adjusting for temp changes does more harm than good.
/**
* Converts pressure to altitude above sea level (ASL) in meters
*/
static float bmp280PressureToAltitude(float* pressure/*, float* groundPressure, float* groundTemp*/)
{
if (*pressure > 0)
{
return ((pow((1015.7f / *pressure), CONST_PF) - 1.0f) * (FIX_TEMP + 273.15f)) / 0.0065f;
}
else
{
return 0;
}
}
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发表于 2022-1-14 17:33:52
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