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ardupilot/libraries/AP_Baro/AP_Baro_MS5611.cpp

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/*
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "AP_Baro_MS5611.h"
#include <utility>
#include <AP_Math/AP_Math.h>
extern const AP_HAL::HAL &hal;
static const uint8_t CMD_MS56XX_RESET = 0x1E;
static const uint8_t CMD_MS56XX_READ_ADC = 0x00;
/* PROM start address */
static const uint8_t CMD_MS56XX_PROM = 0xA0;
/* write to one of these addresses to start pressure conversion */
#define ADDR_CMD_CONVERT_D1_OSR256 0x40
#define ADDR_CMD_CONVERT_D1_OSR512 0x42
#define ADDR_CMD_CONVERT_D1_OSR1024 0x44
#define ADDR_CMD_CONVERT_D1_OSR2048 0x46
#define ADDR_CMD_CONVERT_D1_OSR4096 0x48
/* write to one of these addresses to start temperature conversion */
#define ADDR_CMD_CONVERT_D2_OSR256 0x50
#define ADDR_CMD_CONVERT_D2_OSR512 0x52
#define ADDR_CMD_CONVERT_D2_OSR1024 0x54
#define ADDR_CMD_CONVERT_D2_OSR2048 0x56
#define ADDR_CMD_CONVERT_D2_OSR4096 0x58
#define CONVERSION_TIME_OSR_4096 9.04 * USEC_PER_MSEC
#define CONVERSION_TIME_OSR_2048 4.54 * USEC_PER_MSEC
#define CONVERSION_TIME_OSR_1024 2.28 * USEC_PER_MSEC
#define CONVERSION_TIME_OSR_0512 1.17 * USEC_PER_MSEC
#define CONVERSION_TIME_OSR_0256 0.60 * USEC_PER_MSEC
/*
use an OSR of 1024 to reduce the self-heating effect of the
sensor. Information from MS tells us that some individual sensors
are quite sensitive to this effect and that reducing the OSR can
make a big difference
*/
static const uint8_t ADDR_CMD_CONVERT_PRESSURE = ADDR_CMD_CONVERT_D1_OSR1024;
static const uint8_t ADDR_CMD_CONVERT_TEMPERATURE = ADDR_CMD_CONVERT_D2_OSR1024;
static const uint32_t CONVERSION_TIME = CONVERSION_TIME_OSR_1024;
/*
constructor
*/
AP_Baro_MS56XX::AP_Baro_MS56XX(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
: AP_Baro_Backend(baro)
, _dev(std::move(dev))
{
}
void AP_Baro_MS56XX::_init()
{
if (!_dev) {
AP_HAL::panic("AP_Baro_MS56XX: failed to use device");
}
_sem = hal.util->new_semaphore();
if (!_sem) {
AP_HAL::panic("AP_Baro_MS56XX: failed to create semaphore");
}
_instance = _frontend.register_sensor();
if (!_dev->get_semaphore()->take(10)) {
AP_HAL::panic("PANIC: AP_Baro_MS56XX: failed to take serial semaphore for init");
}
_dev->transfer(&CMD_MS56XX_RESET, 1, nullptr, 0);
hal.scheduler->delay(4);
uint16_t prom[8];
if (!_read_prom(prom)) {
AP_HAL::panic("Can't read PROM");
}
// Save factory calibration coefficients
_cal_reg.c1 = prom[1];
_cal_reg.c2 = prom[2];
_cal_reg.c3 = prom[3];
_cal_reg.c4 = prom[4];
_cal_reg.c5 = prom[5];
_cal_reg.c6 = prom[6];
// Send a command to read temperature first
_dev->transfer(&ADDR_CMD_CONVERT_TEMPERATURE, 1, nullptr, 0);
_last_cmd_usec = AP_HAL::micros();
_state = 0;
memset(&_accum, 0, sizeof(_accum));
_dev->get_semaphore()->give();
/* Request 100Hz update */
_dev->register_periodic_callback(10 * USEC_PER_MSEC,
FUNCTOR_BIND_MEMBER(&AP_Baro_MS56XX::_timer, bool));
}
/**
* MS56XX crc4 method from datasheet for 16 bytes (8 short values)
*/
static uint16_t crc4(uint16_t *data)
{
uint16_t n_rem = 0;
uint8_t n_bit;
for (uint8_t cnt = 0; cnt < 16; cnt++) {
/* uneven bytes */
if (cnt & 1) {
n_rem ^= (uint8_t)((data[cnt >> 1]) & 0x00FF);
} else {
n_rem ^= (uint8_t)(data[cnt >> 1] >> 8);
}
for (n_bit = 8; n_bit > 0; n_bit--) {
if (n_rem & 0x8000) {
n_rem = (n_rem << 1) ^ 0x3000;
} else {
n_rem = (n_rem << 1);
}
}
}
return (n_rem >> 12) & 0xF;
}
uint16_t AP_Baro_MS56XX::_read_prom_word(uint8_t word)
{
const uint8_t reg = CMD_MS56XX_PROM + (word << 1);
uint8_t val[2];
if (!_dev->transfer(&reg, 1, val, 2)) {
return 0;
}
return (val[0] << 8) | val[1];
}
uint32_t AP_Baro_MS56XX::_read_adc()
{
uint8_t val[3];
if (!_dev->transfer(&CMD_MS56XX_READ_ADC, 1, val, 3)) {
return 0;
}
return (val[0] << 16) | (val[1] << 8) | val[2];
}
bool AP_Baro_MS56XX::_read_prom(uint16_t prom[8])
{
/*
* MS5611-01BA datasheet, CYCLIC REDUNDANCY CHECK (CRC): "MS5611-01BA
* contains a PROM memory with 128-Bit. A 4-bit CRC has been implemented
* to check the data validity in memory."
*
* CRC field must me removed for CRC-4 calculation.
*/
for (uint8_t i = 0; i < 8; i++) {
prom[i] = _read_prom_word(i);
}
/* save the read crc */
const uint16_t crc_read = prom[7] & 0xf;
/* remove CRC byte */
prom[7] &= 0xff00;
return crc_read == crc4(prom);
}
bool AP_Baro_MS5637::_read_prom(uint16_t prom[8])
{
/*
* MS5637-02BA03 datasheet, CYCLIC REDUNDANCY CHECK (CRC): "MS5637
* contains a PROM memory with 112-Bit. A 4-bit CRC has been implemented
* to check the data validity in memory."
*
* 8th PROM word must be zeroed and CRC field removed for CRC-4
* calculation.
*/
for (uint8_t i = 0; i < 7; i++) {
prom[i] = _read_prom_word(i);
}
prom[7] = 0;
/* save the read crc */
const uint16_t crc_read = (prom[0] & 0xf000) >> 12;
/* remove CRC byte */
prom[0] &= ~0xf000;
return crc_read == crc4(prom);
}
/*
* Read the sensor with a state machine
* We read one time temperature (state=0) and then 4 times pressure (states 1-4)
*
* Temperature is used to calculate the compensated pressure and doesn't vary
* as fast as pressure. Hence we reuse the same temperature for 4 samples of
* pressure.
*/
bool AP_Baro_MS56XX::_timer(void)
{
/*
* transfer is taking longer than it should or we got stuck by other
* sensors: skip one sample
*/
if (AP_HAL::micros() - _last_cmd_usec < CONVERSION_TIME) {
return true;
}
uint8_t next_cmd;
uint8_t next_state;
uint32_t adc_val = _read_adc();
/*
* If read fails, re-initiate a read command for current state or we are
* stuck
*/
if (adc_val == 0) {
next_state = _state;
} else {
next_state = (_state + 1) % 5;
}
next_cmd = next_state == 0 ? ADDR_CMD_CONVERT_TEMPERATURE
: ADDR_CMD_CONVERT_PRESSURE;
_dev->transfer(&next_cmd, 1, nullptr, 0);
_last_cmd_usec = AP_HAL::micros();
/* if we had a failed read we are all done */
if (adc_val == 0) {
return true;
}
if (_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
if (_state == 0) {
_update_and_wrap_accumulator(&_accum.s_D2, adc_val,
&_accum.d2_count, 32);
} else {
_update_and_wrap_accumulator(&_accum.s_D1, adc_val,
&_accum.d1_count, 128);
}
_sem->give();
_state = next_state;
}
return true;
}
void AP_Baro_MS56XX::_update_and_wrap_accumulator(uint32_t *accum, uint32_t val,
uint8_t *count, uint8_t max_count)
{
*accum += val;
*count += 1;
if (*count == max_count) {
*count = max_count / 2;
*accum = *accum / 2;
}
}
void AP_Baro_MS56XX::update()
{
uint32_t sD1, sD2;
uint8_t d1count, d2count;
if (!_sem->take(HAL_SEMAPHORE_BLOCK_FOREVER)) {
return;
}
if (_accum.d1_count == 0) {
_sem->give();
return;
}
sD1 = _accum.s_D1;
sD2 = _accum.s_D2;
d1count = _accum.d1_count;
d2count = _accum.d2_count;
memset(&_accum, 0, sizeof(_accum));
_sem->give();
if (d1count != 0) {
_D1 = ((float)sD1) / d1count;
}
if (d2count != 0) {
_D2 = ((float)sD2) / d2count;
}
_calculate();
}
/* MS5611 class */
AP_Baro_MS5611::AP_Baro_MS5611(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
: AP_Baro_MS56XX(baro, std::move(dev))
{
_init();
}
// Calculate Temperature and compensated Pressure in real units (Celsius degrees*100, mbar*100).
void AP_Baro_MS5611::_calculate()
{
float dT;
float TEMP;
float OFF;
float SENS;
// Formulas from manufacturer datasheet
// sub -15c temperature compensation is not included
// we do the calculations using floating point allows us to take advantage
// of the averaging of D1 and D1 over multiple samples, giving us more
// precision
dT = _D2-(((uint32_t)_cal_reg.c5)<<8);
TEMP = (dT * _cal_reg.c6)/8388608;
OFF = _cal_reg.c2 * 65536.0f + (_cal_reg.c4 * dT) / 128;
SENS = _cal_reg.c1 * 32768.0f + (_cal_reg.c3 * dT) / 256;
if (TEMP < 0) {
// second order temperature compensation when under 20 degrees C
float T2 = (dT*dT) / 0x80000000;
float Aux = TEMP*TEMP;
float OFF2 = 2.5f*Aux;
float SENS2 = 1.25f*Aux;
TEMP = TEMP - T2;
OFF = OFF - OFF2;
SENS = SENS - SENS2;
}
float pressure = (_D1*SENS/2097152 - OFF)/32768;
float temperature = (TEMP + 2000) * 0.01f;
_copy_to_frontend(_instance, pressure, temperature);
}
/* MS5607 Class */
AP_Baro_MS5607::AP_Baro_MS5607(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
: AP_Baro_MS56XX(baro, std::move(dev))
{
_init();
}
// Calculate Temperature and compensated Pressure in real units (Celsius degrees*100, mbar*100).
void AP_Baro_MS5607::_calculate()
{
float dT;
float TEMP;
float OFF;
float SENS;
// Formulas from manufacturer datasheet
// sub -15c temperature compensation is not included
// we do the calculations using floating point allows us to take advantage
// of the averaging of D1 and D1 over multiple samples, giving us more
// precision
dT = _D2-(((uint32_t)_cal_reg.c5)<<8);
TEMP = (dT * _cal_reg.c6)/8388608;
OFF = _cal_reg.c2 * 131072.0f + (_cal_reg.c4 * dT) / 64;
SENS = _cal_reg.c1 * 65536.0f + (_cal_reg.c3 * dT) / 128;
if (TEMP < 0) {
// second order temperature compensation when under 20 degrees C
float T2 = (dT*dT) / 0x80000000;
float Aux = TEMP*TEMP;
float OFF2 = 61.0f*Aux/16.0f;
float SENS2 = 2.0f*Aux;
TEMP = TEMP - T2;
OFF = OFF - OFF2;
SENS = SENS - SENS2;
}
float pressure = (_D1*SENS/2097152 - OFF)/32768;
float temperature = (TEMP + 2000) * 0.01f;
_copy_to_frontend(_instance, pressure, temperature);
}
/* MS5637 Class */
AP_Baro_MS5637::AP_Baro_MS5637(AP_Baro &baro, AP_HAL::OwnPtr<AP_HAL::Device> dev)
: AP_Baro_MS56XX(baro, std::move(dev))
{
_init();
}
// Calculate Temperature and compensated Pressure in real units (Celsius degrees*100, mbar*100).
void AP_Baro_MS5637::_calculate()
{
int32_t dT, TEMP;
int64_t OFF, SENS;
int32_t raw_pressure = _D1;
int32_t raw_temperature = _D2;
// Formulas from manufacturer datasheet
// sub -15c temperature compensation is not included
dT = raw_temperature - (((uint32_t)_cal_reg.c5) << 8);
TEMP = 2000 + ((int64_t)dT * (int64_t)_cal_reg.c6) / 8388608;
OFF = (int64_t)_cal_reg.c2 * (int64_t)131072 + ((int64_t)_cal_reg.c4 * (int64_t)dT) / (int64_t)64;
SENS = (int64_t)_cal_reg.c1 * (int64_t)65536 + ((int64_t)_cal_reg.c3 * (int64_t)dT) / (int64_t)128;
if (TEMP < 2000) {
// second order temperature compensation when under 20 degrees C
int32_t T2 = ((int64_t)3 * ((int64_t)dT * (int64_t)dT) / (int64_t)8589934592);
int64_t aux = (TEMP - 2000) * (TEMP - 2000);
int64_t OFF2 = 61 * aux / 16;
int64_t SENS2 = 29 * aux / 16;
TEMP = TEMP - T2;
OFF = OFF - OFF2;
SENS = SENS - SENS2;
}
int32_t pressure = ((int64_t)raw_pressure * SENS / (int64_t)2097152 - OFF) / (int64_t)32768;
float temperature = TEMP * 0.01f;
_copy_to_frontend(_instance, (float)pressure, temperature);
}
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