mirror of https://github.com/ArduPilot/ardupilot
287 lines
7.2 KiB
C++
287 lines
7.2 KiB
C++
/*
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APM_BMP085.cpp - Arduino Library for BMP085 absolute pressure sensor
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Code by Jordi Muñoz and Jose Julio. DIYDrones.com
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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Sensor is conected to I2C port
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Sensor End of Conversion (EOC) pin is PC7 (30)
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Variables:
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RawTemp : Raw temperature data
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RawPress : Raw pressure data
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Temp : Calculated temperature (in 0.1ºC units)
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Press : Calculated pressure (in Pa units)
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Methods:
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Init() : Initialization of I2C and read sensor calibration data
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Read() : Read sensor data and calculate Temperature and Pressure
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This function is optimized so the main host don´t need to wait
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You can call this function in your main loop
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It returns a 1 if there are new data.
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Internal functions:
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Command_ReadTemp(): Send commando to read temperature
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Command_ReadPress(): Send commando to read Pressure
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ReadTemp() : Read temp register
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ReadPress() : Read press register
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Calculate() : Calculate Temperature and Pressure in real units
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*/
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extern "C" {
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// AVR LibC Includes
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#include <inttypes.h>
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#include <avr/interrupt.h>
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#include "WConstants.h"
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}
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#include <Wire.h>
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#include "APM_BMP085.h"
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#define BMP085_ADDRESS 0x77 //(0xEE >> 1)
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#define BMP085_EOC 30 // End of conversion pin PC7
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// Constructors ////////////////////////////////////////////////////////////////
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APM_BMP085_Class::APM_BMP085_Class()
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{
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}
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// Public Methods //////////////////////////////////////////////////////////////
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void APM_BMP085_Class::Init(int initialiseWireLib)
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{
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unsigned char tmp;
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byte buff[22];
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int i=0;
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pinMode(BMP085_EOC,INPUT); // End Of Conversion (PC7) input
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if( initialiseWireLib != 0 )
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Wire.begin();
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oss = 3; // Over Sampling setting 3 = High resolution
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BMP085_State = 0; // Initial state
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// We read the calibration data registers
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Wire.beginTransmission(BMP085_ADDRESS);
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Wire.send(0xAA);
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Wire.endTransmission();
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Wire.requestFrom(BMP085_ADDRESS, 22);
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//Wire.endTransmission();
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while(Wire.available())
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{
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buff[i] = Wire.receive(); // receive one byte
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i++;
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}
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ac1 = ((int)buff[0] << 8) | buff[1];
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ac2 = ((int)buff[2] << 8) | buff[3];
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ac3 = ((int)buff[4] << 8) | buff[5];
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ac4 = ((int)buff[6] << 8) | buff[7];
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ac5 = ((int)buff[8] << 8) | buff[9];
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ac6 = ((int)buff[10] << 8) | buff[11];
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b1 = ((int)buff[12] << 8) | buff[13];
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b2 = ((int)buff[14] << 8) | buff[15];
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mb = ((int)buff[16] << 8) | buff[17];
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mc = ((int)buff[18] << 8) | buff[19];
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md = ((int)buff[20] << 8) | buff[21];
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//Send a command to read Temp
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Command_ReadTemp();
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BMP085_State=1;
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}
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// Read the sensor. This is a state machine
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// We read one time Temperature (state=1) and then 4 times Pressure (states 2-5)
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uint8_t APM_BMP085_Class::Read()
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{
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uint8_t result=0;
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if (BMP085_State==1)
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{
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if (digitalRead(BMP085_EOC))
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{
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ReadTemp(); // On state 1 we read temp
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BMP085_State++;
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Command_ReadPress();
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}
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}
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else
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{
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if (BMP085_State==5)
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{
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if (digitalRead(BMP085_EOC))
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{
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ReadPress();
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Calculate();
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BMP085_State = 1; // Start again from state=1
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Command_ReadTemp(); // Read Temp
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result=1; // New pressure reading
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}
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}
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else
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{
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if (digitalRead(BMP085_EOC))
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{
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ReadPress();
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Calculate();
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BMP085_State++;
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Command_ReadPress();
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result=1; // New pressure reading
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}
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}
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}
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return(result);
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}
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// Send command to Read Pressure
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void APM_BMP085_Class::Command_ReadPress()
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{
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Wire.beginTransmission(BMP085_ADDRESS);
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Wire.send(0xF4);
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Wire.send(0x34+(oss<<6)); //write_register(0xF4,0x34+(oversampling_setting<<6));
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Wire.endTransmission();
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}
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// Read Raw Pressure values
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void APM_BMP085_Class::ReadPress()
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{
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byte msb;
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byte lsb;
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byte xlsb;
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Wire.beginTransmission(BMP085_ADDRESS);
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Wire.send(0xF6);
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Wire.endTransmission();
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Wire.requestFrom(BMP085_ADDRESS, 3); // read a byte
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while(!Wire.available()) {
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// waiting
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}
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msb = Wire.receive();
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while(!Wire.available()) {
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// waiting
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}
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lsb = Wire.receive();
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while(!Wire.available()) {
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// waiting
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}
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xlsb = Wire.receive();
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RawPress = (((long)msb<<16) | ((long)lsb<<8) | ((long)xlsb)) >> (8-oss);
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}
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// Send Command to Read Temperature
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void APM_BMP085_Class::Command_ReadTemp()
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{
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Wire.beginTransmission(BMP085_ADDRESS);
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Wire.send(0xF4);
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Wire.send(0x2E);
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Wire.endTransmission();
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}
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// Read Raw Temperature values
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void APM_BMP085_Class::ReadTemp()
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{
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byte tmp;
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Wire.beginTransmission(BMP085_ADDRESS);
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Wire.send(0xF6);
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Wire.endTransmission();
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Wire.beginTransmission(BMP085_ADDRESS);
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Wire.requestFrom(BMP085_ADDRESS,2);
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while(!Wire.available()); // wait
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RawTemp = Wire.receive();
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while(!Wire.available()); // wait
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tmp = Wire.receive();
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RawTemp = RawTemp<<8 | tmp;
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}
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// Calculate Temperature and Pressure in real units.
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void APM_BMP085_Class::Calculate()
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{
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long x1, x2, x3, b3, b5, b6, p;
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unsigned long b4, b7;
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int32_t tmp;
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// See Datasheet page 13 for this formulas
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// Based also on Jee Labs BMP085 example code. Thanks for share.
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// Temperature calculations
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x1 = ((long)RawTemp - ac6) * ac5 >> 15;
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x2 = ((long) mc << 11) / (x1 + md);
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b5 = x1 + x2;
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Temp = (b5 + 8) >> 4;
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// Pressure calculations
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b6 = b5 - 4000;
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x1 = (b2 * (b6 * b6 >> 12)) >> 11;
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x2 = ac2 * b6 >> 11;
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x3 = x1 + x2;
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//b3 = (((int32_t) ac1 * 4 + x3)<<oss + 2) >> 2; // BAD
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//b3 = ((int32_t) ac1 * 4 + x3 + 2) >> 2; //OK for oss=0
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tmp = ac1;
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tmp = (tmp*4 + x3)<<oss;
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b3 = (tmp+2)/4;
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x1 = ac3 * b6 >> 13;
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x2 = (b1 * (b6 * b6 >> 12)) >> 16;
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x3 = ((x1 + x2) + 2) >> 2;
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b4 = (ac4 * (uint32_t) (x3 + 32768)) >> 15;
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b7 = ((uint32_t) RawPress - b3) * (50000 >> oss);
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p = b7 < 0x80000000 ? (b7 * 2) / b4 : (b7 / b4) * 2;
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x1 = (p >> 8) * (p >> 8);
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x1 = (x1 * 3038) >> 16;
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x2 = (-7357 * p) >> 16;
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Press = p + ((x1 + x2 + 3791) >> 4);
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}
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// Constructors ////////////////////////////////////////////////////////////////
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APM_BMP085_HIL_Class::APM_BMP085_HIL_Class()
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{
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}
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// Public Methods //////////////////////////////////////////////////////////////
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void APM_BMP085_HIL_Class::Init(int initialiseWireLib)
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{
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BMP085_State=1;
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}
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// Read the sensor. This is a state machine
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// We read one time Temperature (state=1) and then 4 times Pressure (states 2-5)
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uint8_t APM_BMP085_HIL_Class::Read()
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{
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uint8_t result=0;
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if (BMP085_State==1)
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{
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BMP085_State++;
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}
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else
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{
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if (BMP085_State==5)
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{
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BMP085_State = 1; // Start again from state=1
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result=1; // New pressure reading
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}
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else
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{
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BMP085_State++;
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result=1; // New pressure reading
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}
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}
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return(result);
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}
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void APM_BMP085_HIL_Class::setHIL(float _Temp, float _Press)
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{
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// TODO: map floats to raw
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Temp = _Temp;
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Press = _Press;
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}
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