BME280 library
Revision 0:b32d0acc420d, committed 2015-11-23
- Comitter:
- yasuyuki
- Date:
- Mon Nov 23 07:50:28 2015 +0000
- Child:
- 1:0054d4a28927
- Commit message:
- release
Changed in this revision
| BME280.cpp | Show annotated file Show diff for this revision Revisions of this file |
| BME280.h | Show annotated file Show diff for this revision Revisions of this file |
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/BME280.cpp Mon Nov 23 07:50:28 2015 +0000
@@ -0,0 +1,213 @@
+//**********************
+// BME280.cpp for mbed
+//
+// BME280 bme280(P0_5,P0_4);
+// or
+// I2C i2c(P0_5,P0_4);
+// BME280 bme280(i2c);
+//
+// (C)Copyright 2015 All rights reserved by Y.Onodera
+// http://einstlab.web.fc2.com
+//**********************
+
+#include "mbed.h"
+#include "BME280.h"
+
+BME280::BME280 (PinName sda, PinName scl) : _i2c(sda, scl) {
+ init();
+}
+BME280::BME280 (I2C& p_i2c) : _i2c(p_i2c) {
+ init();
+}
+
+
+unsigned char BME280::get(unsigned char a)
+{
+
+ buf[0] = a; // register
+ _i2c.write(BME280_ADDR, buf, 1); // with stop
+ // get data
+ _i2c.read( BME280_ADDR, buf, 1);
+ return buf[0];
+
+}
+
+void BME280::set(unsigned char a, unsigned char b)
+{
+
+ buf[0] = a; // register
+ buf[1] = b;
+ _i2c.write(BME280_ADDR, buf, 2); // with stop
+
+}
+
+
+void BME280::getALL()
+{
+ // set ctrl_meas : forced mode
+ set(ctrl_meas, 0x25);
+
+ // wait status
+ if(get(status) != 0)wait_ms(1);
+
+ // get temp
+ temp.XLSB = get(temp_xlsb);
+ temp.LSB = get(temp_lsb);
+ temp.MSB = get(temp_msb);
+ temp.dummy = 0;
+
+ // get press
+ press.XLSB = get(press_xlsb);
+ press.LSB = get(press_lsb);
+ press.MSB = get(press_msb);
+ press.dummy = 0;
+
+ // get hum
+ hum.LSB = get(hum_lsb);
+ hum.MSB = get(hum_msb);
+
+
+ // compensation
+ t = BME280_compensate_T_int32(temp.s32>>12);
+ p = BME280_compensate_P_int64(press.s32>>12);
+ h = BME280_compensate_H_int32((signed int)hum.u16);
+}
+
+unsigned int BME280::humidity()
+{
+
+ // get hum
+ getALL();
+ return h;
+
+}
+
+signed int BME280::temperature()
+{
+
+ // get temp
+ getALL();
+ return t;
+
+}
+
+unsigned int BME280::pressure()
+{
+
+ // get hum
+ getALL();
+ return p;
+
+}
+
+void BME280::init()
+{
+
+ // get calibrations
+ calib.LSB = get(calib00);
+ calib.MSB = get(calib01);
+ dig_T1 = calib.u16;
+ calib.LSB = get(calib02);
+ calib.MSB = get(calib03);
+ dig_T2 = calib.s16;
+ calib.LSB = get(calib04);
+ calib.MSB = get(calib05);
+ dig_T3 = calib.s16;
+ calib.LSB = get(calib06);
+ calib.MSB = get(calib07);
+ dig_P1 = calib.u16;
+ calib.LSB = get(calib08);
+ calib.MSB = get(calib09);
+ dig_P2 = calib.s16;
+ calib.LSB = get(calib10);
+ calib.MSB = get(calib11);
+ dig_P3 = calib.s16;
+ calib.LSB = get(calib12);
+ calib.MSB = get(calib13);
+ dig_P4 = calib.s16;
+ calib.LSB = get(calib14);
+ calib.MSB = get(calib15);
+ dig_P5 = calib.s16;
+ calib.LSB = get(calib16);
+ calib.MSB = get(calib17);
+ dig_P6 = calib.s16;
+ calib.LSB = get(calib18);
+ calib.MSB = get(calib19);
+ dig_P7 = calib.s16;
+ calib.LSB = get(calib20);
+ calib.MSB = get(calib21);
+ dig_P8 = calib.s16;
+ calib.LSB = get(calib22);
+ calib.MSB = get(calib23);
+ dig_P9 = calib.s16;
+ dig_H1 = get(calib25);
+ calib.LSB = get(calib26);
+ calib.MSB = get(calib27);
+ dig_H2 = calib.s16;
+ dig_H3 = get(calib28);
+ calib.MSB = get(calib29);
+ calib.LSB = get(calib30) << 4;
+ dig_H4 = calib.s16>>4;
+ calib.LSB = get(calib30);
+ calib.MSB = get(calib31);
+ dig_H5 = calib.s16>>4;
+ dig_H6 = get(calib32);
+
+ // Set configuration
+ set(config, 0x00);
+ set(ctrl_hum, 0x01);
+
+}
+
+// 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
+BME280_S32_t BME280::BME280_compensate_T_int32(BME280_S32_t adc_T)
+{
+ BME280_S32_t var1, var2, T;
+ var1 = ((((adc_T>>3) - ((BME280_S32_t)dig_T1<<1))) * ((BME280_S32_t)dig_T2)) >> 11;
+ var2 = (((((adc_T>>4) - ((BME280_S32_t)dig_T1)) * ((adc_T>>4) - ((BME280_S32_t)dig_T1))) >> 12) *
+ ((BME280_S32_t)dig_T3)) >> 14;
+ t_fine = var1 + var2;
+ T = (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
+BME280_U32_t BME280::BME280_compensate_P_int64(BME280_S32_t adc_P)
+{
+ BME280_S64_t var1, var2, p;
+ var1 = ((BME280_S64_t)t_fine) - 128000;
+ var2 = var1 * var1 * (BME280_S64_t)dig_P6;
+ var2 = var2 + ((var1*(BME280_S64_t)dig_P5)<<17);
+ var2 = var2 + (((BME280_S64_t)dig_P4)<<35);
+ var1 = ((var1 * var1 * (BME280_S64_t)dig_P3)>>8) + ((var1 * (BME280_S64_t)dig_P2)<<12);
+ var1 = (((((BME280_S64_t)1)<<47)+var1))*((BME280_S64_t)dig_P1)>>33;
+ if (var1 == 0)
+ {
+ return 0; // avoid exception caused by division by zero
+ }
+ p = 1048576-adc_P;
+ p = (((p<<31)-var2)*3125)/var1;
+ var1 = (((BME280_S64_t)dig_P9) * (p>>13) * (p>>13)) >> 25;
+ var2 = (((BME280_S64_t)dig_P8) * p) >> 19;
+ p = ((p + var1 + var2) >> 8) + (((BME280_S64_t)dig_P7)<<4);
+ return (BME280_U32_t)p;
+}
+
+// Returns humidity in %RH as unsigned 32 bit integer in Q22.10 format (22 integer and 10 fractional bits).
+// Output value of "47445" represents 47445/1024 = 46.333 %RH
+BME280_U32_t BME280::BME280_compensate_H_int32(BME280_S32_t adc_H)
+{
+ BME280_S32_t v_x1_u32r;
+ v_x1_u32r = (t_fine - ((BME280_S32_t)76800));
+ v_x1_u32r = (((((adc_H << 14) - (((BME280_S32_t)dig_H4) << 20) - (((BME280_S32_t)dig_H5) * v_x1_u32r)) +
+ ((BME280_S32_t)16384)) >> 15) * (((((((v_x1_u32r * ((BME280_S32_t)dig_H6)) >> 10) * (((v_x1_u32r *
+ ((BME280_S32_t)dig_H3)) >> 11) + ((BME280_S32_t)32768))) >> 10) + ((BME280_S32_t)2097152)) *
+ ((BME280_S32_t)dig_H2) + 8192) >> 14));
+ v_x1_u32r = (v_x1_u32r - (((((v_x1_u32r >> 15) * (v_x1_u32r >> 15)) >> 7) * ((BME280_S32_t)dig_H1)) >> 4));
+ v_x1_u32r = (v_x1_u32r < 0 ? 0 : v_x1_u32r);
+ v_x1_u32r = (v_x1_u32r > 419430400 ? 419430400 : v_x1_u32r);
+ return (BME280_U32_t)(v_x1_u32r>>12);
+}
+
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/BME280.h Mon Nov 23 07:50:28 2015 +0000
@@ -0,0 +1,150 @@
+//**********************
+// BME280.h for mbed
+//
+// (C)Copyright 2015 All rights reserved by Y.Onodera
+// http://einstlab.web.fc2.com
+//**********************
+#ifndef BME280_H_
+#define BME280_H_
+
+#define BME280_ADDR 0xEC
+#define hum_lsb 0xFE
+#define hum_msb 0xFD
+#define temp_xlsb 0xFC
+#define temp_lsb 0xFB
+#define temp_msb 0xFA
+#define press_xlsb 0xF9
+#define press_lsb 0xF8
+#define press_msb 0xF7
+#define config 0xF5
+#define ctrl_meas 0xF4
+#define status 0xF3
+#define ctrl_hum 0xF2
+#define calib41 0xF0
+#define calib40 0xEF
+#define calib39 0xEE
+#define calib38 0xED
+#define calib37 0xEC
+#define calib36 0xEB
+#define calib35 0xEA
+#define calib34 0xE9
+#define calib33 0xE8
+#define calib32 0xE7
+#define calib31 0xE6
+#define calib30 0xE5
+#define calib29 0xE4
+#define calib28 0xE3
+#define calib27 0xE2
+#define calib26 0xE1
+#define reset 0xE0
+#define id 0xD0
+#define calib25 0xA1
+#define calib24 0xA0
+#define calib23 0x9F
+#define calib22 0x9E
+#define calib21 0x9D
+#define calib20 0x9C
+#define calib19 0x9B
+#define calib18 0x9A
+#define calib17 0x99
+#define calib16 0x98
+#define calib15 0x97
+#define calib14 0x96
+#define calib13 0x95
+#define calib12 0x94
+#define calib11 0x93
+#define calib10 0x92
+#define calib09 0x91
+#define calib08 0x90
+#define calib07 0x8F
+#define calib06 0x8E
+#define calib05 0x8D
+#define calib04 0x8C
+#define calib03 0x8B
+#define calib02 0x8A
+#define calib01 0x89
+#define calib00 0x88
+
+#include "mbed.h"
+
+// see BST-BME280-DS001-10
+#define BME280_S32_t signed int
+#define BME280_S64_t signed long long
+#define BME280_U32_t unsigned int
+
+
+union WORD32 {
+ signed int s32;
+ unsigned int u32;
+ struct {
+ unsigned char dummy;
+ unsigned char XLSB;
+ unsigned char LSB;
+ unsigned char MSB;
+ };
+};
+
+union WORD16 {
+ signed short s16;
+ unsigned short u16;
+ struct {
+ unsigned char LSB;
+ unsigned char MSB;
+ };
+};
+
+
+class BME280{
+public:
+ BME280 (PinName sda, PinName scl);
+ BME280 (I2C& p_i2c);
+
+ void set(unsigned char a,unsigned char b);
+ unsigned char get(unsigned char a);
+ void getALL();
+ unsigned int humidity();
+ signed int temperature();
+ unsigned int pressure();
+ void init();
+
+protected:
+
+ I2C _i2c;
+
+ union WORD16 calib;
+ union WORD16 hum;
+ union WORD32 temp;
+ union WORD32 press;
+ char buf[8];
+
+ unsigned short dig_T1;
+ signed short dig_T2;
+ signed short dig_T3;
+ unsigned short dig_P1;
+ signed short dig_P2;
+ signed short dig_P3;
+ signed short dig_P4;
+ signed short dig_P5;
+ signed short dig_P6;
+ signed short dig_P7;
+ signed short dig_P8;
+ signed short dig_P9;
+ unsigned char dig_H1;
+ signed short dig_H2;
+ unsigned char dig_H3;
+ signed short dig_H4;
+ signed short dig_H5;
+ signed char dig_H6;
+
+ BME280_S32_t t_fine;
+ BME280_S32_t BME280_compensate_T_int32(BME280_S32_t adc_T);
+ BME280_U32_t BME280_compensate_P_int64(BME280_S32_t adc_P);
+ BME280_U32_t BME280_compensate_H_int32(BME280_S32_t adc_H);
+ unsigned int t;
+ signed int p;
+ signed int h;
+};
+
+#endif /* BME280_H_ */
+
+