mirror of https://github.com/ArduPilot/ardupilot
262 lines
7.2 KiB
C++
262 lines
7.2 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
|
||
/*
|
||
APM_MS5611.cpp - Arduino Library for MS5611-01BA01 absolute pressure sensor
|
||
Code by Jose Julio, Pat Hickey and Jordi Muñoz. DIYDrones.com
|
||
|
||
This library is free software; you can redistribute it and/or
|
||
modify it under the terms of the GNU Lesser General Public
|
||
License as published by the Free Software Foundation; either
|
||
version 2.1 of the License, or (at your option) any later version.
|
||
|
||
Sensor is conected to standard SPI port
|
||
Chip Select pin: Analog2 (provisional until Jordi defines the pin)!!
|
||
|
||
Variables:
|
||
Temp : Calculated temperature (in Celsius degrees * 100)
|
||
Press : Calculated pressure (in mbar units * 100)
|
||
|
||
|
||
Methods:
|
||
init() : Initialization and sensor reset
|
||
read() : Read sensor data and _calculate Temperature, Pressure and Altitude
|
||
This function is optimized so the main host don´t need to wait
|
||
You can call this function in your main loop
|
||
Maximum data output frequency 100Hz - this allows maximum oversampling in the chip ADC
|
||
It returns a 1 if there are new data.
|
||
get_pressure() : return pressure in mbar*100 units
|
||
get_temperature() : return temperature in celsius degrees*100 units
|
||
get_altitude() : return altitude in meters
|
||
|
||
Internal functions:
|
||
_calculate() : Calculate Temperature and Pressure (temperature compensated) in real units
|
||
|
||
|
||
*/
|
||
|
||
#include <SPI.h>
|
||
#include "AP_Baro_MS5611.h"
|
||
|
||
|
||
/* on APM v.24 MS5661_CS is PG1 (Arduino pin 40) */
|
||
#define MS5611_CS 40
|
||
|
||
#define CMD_MS5611_RESET 0x1E
|
||
#define CMD_MS5611_PROM_Setup 0xA0
|
||
#define CMD_MS5611_PROM_C1 0xA2
|
||
#define CMD_MS5611_PROM_C2 0xA4
|
||
#define CMD_MS5611_PROM_C3 0xA6
|
||
#define CMD_MS5611_PROM_C4 0xA8
|
||
#define CMD_MS5611_PROM_C5 0xAA
|
||
#define CMD_MS5611_PROM_C6 0xAC
|
||
#define CMD_MS5611_PROM_CRC 0xAE
|
||
#define CMD_CONVERT_D1_OSR4096 0x48 // Maximum resolution (oversampling)
|
||
#define CMD_CONVERT_D2_OSR4096 0x58 // Maximum resolution (oversampling)
|
||
|
||
uint32_t AP_Baro_MS5611::_s_D1;
|
||
uint32_t AP_Baro_MS5611::_s_D2;
|
||
uint8_t AP_Baro_MS5611::_state;
|
||
long AP_Baro_MS5611::_timer;
|
||
bool AP_Baro_MS5611::_sync_access;
|
||
bool AP_Baro_MS5611::_updated;
|
||
|
||
uint8_t AP_Baro_MS5611::_spi_read(uint8_t reg)
|
||
{
|
||
uint8_t dump;
|
||
uint8_t return_value;
|
||
uint8_t addr = reg; // | 0x80; // Set most significant bit
|
||
digitalWrite(MS5611_CS, LOW);
|
||
dump = SPI.transfer(addr);
|
||
return_value = SPI.transfer(0);
|
||
digitalWrite(MS5611_CS, HIGH);
|
||
return return_value;
|
||
}
|
||
|
||
uint16_t AP_Baro_MS5611::_spi_read_16bits(uint8_t reg)
|
||
{
|
||
uint8_t dump, byteH, byteL;
|
||
uint16_t return_value;
|
||
uint8_t addr = reg; // | 0x80; // Set most significant bit
|
||
digitalWrite(MS5611_CS, LOW);
|
||
dump = SPI.transfer(addr);
|
||
byteH = SPI.transfer(0);
|
||
byteL = SPI.transfer(0);
|
||
digitalWrite(MS5611_CS, HIGH);
|
||
return_value = ((uint16_t)byteH<<8) | (byteL);
|
||
return return_value;
|
||
}
|
||
|
||
uint32_t AP_Baro_MS5611::_spi_read_adc()
|
||
{
|
||
uint8_t dump,byteH,byteM,byteL;
|
||
uint32_t return_value;
|
||
uint8_t addr = 0x00;
|
||
digitalWrite(MS5611_CS, LOW);
|
||
dump = SPI.transfer(addr);
|
||
byteH = SPI.transfer(0);
|
||
byteM = SPI.transfer(0);
|
||
byteL = SPI.transfer(0);
|
||
digitalWrite(MS5611_CS, HIGH);
|
||
return_value = (((uint32_t)byteH)<<16) | (((uint32_t)byteM)<<8) | (byteL);
|
||
return return_value;
|
||
}
|
||
|
||
|
||
void AP_Baro_MS5611::_spi_write(uint8_t reg)
|
||
{
|
||
uint8_t dump;
|
||
digitalWrite(MS5611_CS, LOW);
|
||
dump = SPI.transfer(reg);
|
||
digitalWrite(MS5611_CS, HIGH);
|
||
}
|
||
|
||
// Public Methods //////////////////////////////////////////////////////////////
|
||
// SPI should be initialized externally
|
||
bool AP_Baro_MS5611::init( AP_PeriodicProcess *scheduler )
|
||
{
|
||
pinMode(MS5611_CS, OUTPUT); // Chip select Pin
|
||
digitalWrite(MS5611_CS, HIGH);
|
||
delay(1);
|
||
|
||
_spi_write(CMD_MS5611_RESET);
|
||
delay(4);
|
||
|
||
// We read the factory calibration
|
||
// The on-chip CRC is not used
|
||
C1 = _spi_read_16bits(CMD_MS5611_PROM_C1);
|
||
C2 = _spi_read_16bits(CMD_MS5611_PROM_C2);
|
||
C3 = _spi_read_16bits(CMD_MS5611_PROM_C3);
|
||
C4 = _spi_read_16bits(CMD_MS5611_PROM_C4);
|
||
C5 = _spi_read_16bits(CMD_MS5611_PROM_C5);
|
||
C6 = _spi_read_16bits(CMD_MS5611_PROM_C6);
|
||
|
||
|
||
//Send a command to read Temp first
|
||
_spi_write(CMD_CONVERT_D2_OSR4096);
|
||
_timer = micros();
|
||
_state = 1;
|
||
Temp=0;
|
||
Press=0;
|
||
|
||
scheduler->register_process( AP_Baro_MS5611::_update );
|
||
|
||
healthy = true;
|
||
return true;
|
||
}
|
||
|
||
|
||
// Read the sensor. This is a state machine
|
||
// We read one time Temperature (state=1) and then 4 times Pressure (states 2-5)
|
||
// temperature does not change so quickly...
|
||
void AP_Baro_MS5611::_update(uint32_t tnow)
|
||
{
|
||
if (_sync_access) return;
|
||
|
||
// Throttle read rate to 100hz maximum.
|
||
// note we use 9500us here not 10000us
|
||
// the read rate will end up at exactly 100hz because the Periodic Timer fires at 1khz
|
||
if (tnow - _timer < 9500) {
|
||
return;
|
||
}
|
||
|
||
_timer = tnow;
|
||
|
||
if (_state == 1) {
|
||
_s_D2 = _spi_read_adc(); // On state 1 we read temp
|
||
_state++;
|
||
_spi_write(CMD_CONVERT_D1_OSR4096); // Command to read pressure
|
||
} else if (_state == 5) {
|
||
_s_D1 = _spi_read_adc();
|
||
_state = 1; // Start again from state = 1
|
||
_spi_write(CMD_CONVERT_D2_OSR4096); // Command to read temperature
|
||
_updated = true; // New pressure reading
|
||
} else {
|
||
_s_D1 = _spi_read_adc();
|
||
_state++;
|
||
_spi_write(CMD_CONVERT_D1_OSR4096); // Command to read pressure
|
||
_updated = true; // New pressure reading
|
||
}
|
||
}
|
||
|
||
uint8_t AP_Baro_MS5611::read()
|
||
{
|
||
_sync_access = true;
|
||
bool updated = _updated;
|
||
_updated = 0;
|
||
if (updated > 0) {
|
||
D1 = _s_D1;
|
||
D2 = _s_D2;
|
||
_raw_press = D1;
|
||
_raw_temp = D2;
|
||
}
|
||
_sync_access = false;
|
||
_calculate();
|
||
return updated ? 1 : 0;
|
||
}
|
||
|
||
// Calculate Temperature and compensated Pressure in real units (Celsius degrees*100, mbar*100).
|
||
void AP_Baro_MS5611::_calculate()
|
||
{
|
||
int32_t dT;
|
||
long long TEMP; // 64 bits
|
||
long long OFF;
|
||
long long SENS;
|
||
long long P;
|
||
|
||
// Formulas from manufacturer datasheet
|
||
// as per data sheet some intermediate results require over 32 bits, therefore
|
||
// we define parameters as 64 bits to prevent overflow on operations
|
||
// sub -20c temperature compensation is not included
|
||
dT = D2-((long)C5*256);
|
||
TEMP = 2000 + ((long long)dT * C6)/8388608;
|
||
OFF = (long long)C2 * 65536 + ((long long)C4 * dT ) / 128;
|
||
SENS = (long long)C1 * 32768 + ((long long)C3 * dT) / 256;
|
||
|
||
if (TEMP < 2000){ // second order temperature compensation
|
||
long long T2 = (long long)dT*dT / 2147483648;
|
||
long long Aux_64 = (TEMP-2000)*(TEMP-2000);
|
||
long long OFF2 = 5*Aux_64/2;
|
||
long long SENS2 = 5*Aux_64/4;
|
||
TEMP = TEMP - T2;
|
||
OFF = OFF - OFF2;
|
||
SENS = SENS - SENS2;
|
||
}
|
||
|
||
P = (D1*SENS/2097152 - OFF)/32768;
|
||
Temp = TEMP;
|
||
Press = P;
|
||
}
|
||
|
||
int32_t AP_Baro_MS5611::get_pressure()
|
||
{
|
||
return(Press);
|
||
}
|
||
|
||
int16_t AP_Baro_MS5611::get_temperature()
|
||
{
|
||
// callers want the temperature in 0.1C units
|
||
return(Temp/10);
|
||
}
|
||
|
||
// Return altitude using the standard 1013.25 mbar at sea level reference
|
||
float AP_Baro_MS5611::get_altitude()
|
||
{
|
||
float tmp_float;
|
||
float Altitude;
|
||
|
||
tmp_float = (Press / 101325.0);
|
||
tmp_float = pow(tmp_float, 0.190295);
|
||
Altitude = 44330 * (1.0 - tmp_float);
|
||
|
||
return (Altitude);
|
||
}
|
||
|
||
int32_t AP_Baro_MS5611::get_raw_pressure() {
|
||
return _raw_press;
|
||
}
|
||
|
||
int32_t AP_Baro_MS5611::get_raw_temp() {
|
||
return _raw_temp;
|
||
}
|
||
|
||
|