LPS25H.cpp

00001 /*
00002  * mbed library program
00003  *  LPS25H MEMS pressure sensor: 260-1260 hPa absolute digital output barometer
00004  *   made by STMicroelectronics
00005  *   http://www.st-japan.co.jp/web/catalog/sense_power/FM89/SC1316/PF255230
00006  * Copyright (c) 2015,'17 Kenji Arai / JH1PJL
00007  *      Created: Feburary  21st, 2015
00008  *      Revised: August    21st, 2017
00009  */
00010 
00011 #include "LPS25H.h"
00012 
00013 LPS25H::LPS25H (PinName p_sda, PinName p_scl) :
00014  _i2c_p(new I2C(p_sda, p_scl)), _i2c(*_i2c_p)
00015 {
00016     LPS25H_addr = LPS25H_V_CHIP_ADDR;
00017     //LPS25H_mode = FIFO_HW_FILTER;
00018     init();
00019 }
00020 // Initialize
00021 void LPS25H::init(void) {
00022     _i2c.frequency(100000);
00023     //if (LPS25H_mode == FIFO_HW_FILTER){
00024         dt[0] = LPS25H_RES_CONF;
00025         dt[1] = 0x05;
00026         _i2c.write(LPS25H_addr, dt, 2, false);
00027         dt[0] = LPS25H_FIFO_CTRL;
00028         dt[1] = 0xdf;
00029         _i2c.write(LPS25H_addr, dt, 2, false);
00030         dt[0] = LPS25H_CTRL_REG2;
00031         dt[1] = 0x40;
00032         _i2c.write(LPS25H_addr, dt, 2, false);
00033         dt[0] = LPS25H_CTRL_REG1;
00034         dt[1] = 0x90;
00035         _i2c.write(LPS25H_addr, dt, 2, false);
00036     /*} else {
00037         dt[0] = LPS25H_CTRL_REG2;
00038         dt[1] = 0x0;
00039         _i2c.write(LPS25H_addr, dt, 2, false);
00040         dt[0] = LPS25H_CTRL_REG1;
00041         dt[1] = CR_STD_SET;
00042         _i2c.write(LPS25H_addr, dt, 2, false);
00043     }*/
00044 }
00045 
00046 // Start conv. and get all data
00047 void LPS25H::get(void) {
00048     dt[0] = LPS25H_PRESS_POUT_XL | 0x80;
00049     _i2c.write(LPS25H_addr, dt, 1, true);
00050     _i2c.read(LPS25H_addr, dt, 3, false);
00051     press = dt[2] << 16 | dt[1] << 8 | dt[0];
00052     alt = (1-pow((press/4096)/1013.25,0.190284))*145366.45;
00053 }
00054 
00055 float LPS25H::pressure() {
00056     return (float)press / 4096;
00057 }
00058 
00059 float LPS25H::altitude(void) {
00060     return  alt/3.280839895;
00061 }