common/I2C/BMP280.c

   1 #define F_CPU 8000000UL
   2 #include <avr/io.h>
   3 #include <avr/interrupt.h>
   4 #include <util/delay.h>
   5 #include <avr/wdt.h>
   6 #include <avr/sleep.h>
   7 #include "USI_TWI_Master.h"
   8
   9 uint16_t dig_T1;
  10 int16_t dig_T2;
  11 int16_t dig_T3;
  12 uint16_t dig_P1;
  13 int16_t dig_P2;
  14 int16_t dig_P3;
  15 int16_t dig_P4;
  16 int16_t dig_P5;
  17 int16_t dig_P6;
  18 int16_t dig_P7;
  19 int16_t dig_P8;
  20 int16_t dig_P9;
  21
  22
  23
  24
  25 short bmp280ReadShort(unsigned char address)
  26 {
  27         char msb, lsb;
  28         short data;
  29         I2c_StartCondition();
  30         I2c_WriteByte(0xEC);
  31         I2c_WriteByte(address);
  32         I2c_StopCondition();
  33         I2c_StartCondition();
  34         I2c_WriteByte(0xED);
  35         lsb=I2c_ReadByte(ACK);
  36         msb=I2c_ReadByte(NO_ACK);
  37         I2c_StopCondition();
  38
  39
  40
  41         data = msb << 8;
  42         data |= lsb;
  43
  44         return data;
  45 }
  46
  47 void bmp280Init(void) {
  48         dig_T1=bmp280ReadShort(0x88);
  49         dig_T2=bmp280ReadShort(0x8A);
  50         dig_T3=bmp280ReadShort(0x8C);
  51         dig_P1=bmp280ReadShort(0x8E);
  52         dig_P2=bmp280ReadShort(0x90);
  53         dig_P3=bmp280ReadShort(0x92);
  54         dig_P4=bmp280ReadShort(0x94);
  55         dig_P5=bmp280ReadShort(0x96);
  56         dig_P6=bmp280ReadShort(0x98);
  57         dig_P7=bmp280ReadShort(0x9A);
  58         dig_P8=bmp280ReadShort(0x9C);
  59         dig_P9=bmp280ReadShort(0x9E);
  60         I2c_StartCondition();
  61         I2c_WriteByte(0xEC);
  62         I2c_WriteByte(0xF4);
  63         I2c_WriteByte(0b01010111); //2x Temp over 16x Press over   Normal mode
  64         I2c_WriteByte(0b11100000);  //4s time / no IIfilter
  65         I2c_StopCondition();
  66
  67
  68 }
  69 int32_t bmp280ReadTemp(void) {
  70         uint8_t msb, lsb,xlsb;
  71         volatile int32_t data;
  72         I2c_StartCondition();
  73         I2c_WriteByte(0xEC);
  74         I2c_WriteByte(0xFA);
  75         I2c_StopCondition();
  76         I2c_StartCondition();
  77         I2c_WriteByte(0xED);
  78         msb=I2c_ReadByte(ACK);
  79         lsb=I2c_ReadByte(ACK);
  80         xlsb=I2c_ReadByte(NO_ACK);
  81         I2c_StopCondition();
  82
  83         data = (int32_t)msb << 12;
  84         data |= (int16_t)lsb<<4;
  85         data|=xlsb>>4;
  86
  87                 return data;
  88
  89
  90 }
  91 int32_t bmp280ReadPressure(uint8_t oss) {
  92                 uint8_t msb, lsb,xlsb;
  93                 volatile int32_t data;
  94                 I2c_StartCondition();
  95                 I2c_WriteByte(0xEC);
  96                 I2c_WriteByte(0xF7);
  97                 I2c_StopCondition();
  98                 I2c_StartCondition();
  99                 I2c_WriteByte(0xED);
 100                 msb=I2c_ReadByte(ACK);
 101                 lsb=I2c_ReadByte(ACK);
 102                 xlsb=I2c_ReadByte(NO_ACK);
 103                 I2c_StopCondition();
 104
 105                 data = (int32_t)msb << 12;
 106                 data |= (int16_t)lsb<<4;
 107                 data|=xlsb>>4;
 108
 109                 return data;
 110
 111
 112 }
 113 void bmp280ConvertInt(int32_t * temperature,uint32_t *pressure,uint8_t oss) {
 114         int32_t var1,var2,T,t_fine;
 115
 116
 117         int32_t adc_T=bmp280ReadTemp();
 118         var1 = ((((adc_T>>3) - ((int32_t)dig_T1<<1))) * ((int32_t)dig_T2)) >> 11;
 119         var2 = ((((((adc_T>>4) - ((int32_t)dig_T1)) * ((adc_T>>4) - (int32_t)dig_T1))) >> 12) *((int32_t)dig_T3)) >> 14;
 120         t_fine = var1 + var2;
 121         T = (t_fine * 5 + 128) >> 8;
 122         *temperature=T;
 123         int32_t adc_P= bmp280ReadPressure(oss);
 124         uint32_t p;
 125         var1 = (((int32_t)t_fine)>>1) - (int32_t)64000;
 126         var2 = (((var1>>2) * (var1>>2)) >> 11 ) * ((int32_t)dig_P6);
 127         var2 = var2 + ((var1*((int32_t)dig_P5))<<1);
 128         var2 = (var2>>2)+(((int32_t)dig_P4)<<16);
 129         var1 = (((dig_P3 * (((var1>>2) * (var1>>2)) >> 13 )) >> 3) + ((((int32_t)dig_P2) * var1)>>1))>>18;
 130         var1 =((((32768+var1))*((int32_t)dig_P1))>>15);
 131         if (var1 == 0) {
 132                 return ; // avoid exception caused by division by zero
 133         }
 134         p = (((uint32_t)(((int32_t)1048576)-adc_P)-(var2>>12)))*3125;
 135         if (p < 0x80000000){
 136                 p = (p << 1) / ((uint32_t)var1);
 137                 }else{
 138                 p = (p / (uint32_t)var1) * 2;
 139         }
 140         var1 = (((int32_t)dig_P9) * ((int32_t)(((p>>3) * (p>>3))>>13)))>>12;
 141         var2 = (((int32_t)(p>>2)) * ((int32_t)dig_P8))>>13;
 142         p = (uint32_t)((int32_t)p + ((var1 + var2 + dig_P7) >> 4));
 143         *pressure=p;
 144
 145 }
 146 void bmp280Convert(double * temperature, double * pressure,uint8_t oss) {
 147
 148         uint32_t p;
 149         int32_t T;
 150         bmp280ConvertInt(&T,&p,oss);
 151         *temperature=T/100.0;
 152         *pressure=p/100.0;
 153 }
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