ardupilot/libraries/AP_TemperatureSensor/AP_TemperatureSensor_MAX318...

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/*
* Copyright (C) 2023 Kraus Hamdani Aerospace Inc. All rights reserved.
*
* This file 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 file 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/>.
*
* Code by Tom Pittenger
*/
/*
Implements SPI driver for MAX31865 digital RTD Temperature converter
*/
#include "AP_TemperatureSensor_MAX31865.h"
#if AP_TEMPERATURE_SENSOR_MAX31865_ENABLED
#include <stdio.h>
#include <AP_Math/AP_Math.h>
#include <AP_HAL/utility/sparse-endian.h>
extern const AP_HAL::HAL &hal;
#define MAX31865_REG_WRITE_ADDR_OFFSET 0x80
#define MAX31865_REG_CONFIG_READ 0x00
#define MAX31865_REG_CONFIG_WRITE (MAX31865_REG_CONFIG_READ | MAX31865_REG_WRITE_ADDR_OFFSET)
#define MAX31865_REG_DATA_MSB 0x01
#define MAX31865_REG_DATA_LSB 0x02
#define MAX31865_REG_HIGH_FAULT_THRESH_MSB 0x03
#define MAX31865_REG_HIGH_FAULT_THRESH_LSB 0x04
#define MAX31865_REG_LOW_FAULT_THRESH_MSB 0x05
#define MAX31865_REG_LOW_FAULT_THRESH_LSB 0x06
#define MAX31865_REG_FAULT_STATUS_READ 0x07
#define MAX31865_REG_FAULT_STATUS_WRITE (MAX31865_REG_FAULT_STATUS_READ | MAX31865_REG_WRITE_ADDR_OFFSET)
// Vbias = ON (must be on for automatic mode)
// Conversion mode: Auto
// Fault Status: 1set 1 to Clear all latched faults
#define MAX31865_CONFIG_VALUE (0b11000010)
#define MAX31865_DEBUGGING 0
#if MAX31865_DEBUGGING
#ifdef HAL_BUILD_AP_PERIPH
extern "C" {
void can_printf(const char *fmt, ...);
}
//# define Debug(fmt, args ...) do { can_printf("%s:%d: " fmt "\n", __FUNCTION__, __LINE__, ## args); hal.scheduler->delay(1); } while(0)
# define Debug(fmt, args ...) do { can_printf(fmt, ## args); } while(0)
#else
# define Debug(fmt, args ...) do {hal.console->printf("%s:%d: " fmt "\n", __FUNCTION__, __LINE__, ## args); hal.scheduler->delay(1); } while(0)
#endif // HAL_BUILD_AP_PERIPH
#else
# define Debug(fmt, args ...)
#endif // MAX31865_DEBUGGING
void AP_TemperatureSensor_MAX31865::init()
{
if (_dev) {
return;
}
// also look for "max31865_n" where n is the addr param.
char name[12] = "max31865";
if (_params.bus_address > 0 && _params.bus_address <= 9) {
name[8] = '_';
name[9] = '0' + _params.bus_address; // convert bus_address to ascii
name[10] = 0;
}
_dev = std::move(hal.spi->get_device(name));
if (!_dev) {
return;
}
WITH_SEMAPHORE(_dev->get_semaphore());
_dev->set_speed(AP_HAL::Device::SPEED_LOW);
_dev->write_register(MAX31865_REG_CONFIG_WRITE, MAX31865_CONFIG_VALUE);
_dev->set_speed(AP_HAL::Device::SPEED_HIGH);
/* Request 5Hz update */
_dev->register_periodic_callback(200 * AP_USEC_PER_MSEC,
FUNCTOR_BIND_MEMBER(&AP_TemperatureSensor_MAX31865::thread_tick, void));
}
void AP_TemperatureSensor_MAX31865::thread_tick()
{
uint16_t raw_data;
if (!_dev->read_registers(MAX31865_REG_DATA_MSB, (uint8_t *)&raw_data, sizeof(raw_data))) {
return;
}
// 16bit byte swap
const uint16_t data = htobe16(raw_data);
// fault is LSB bit, temperature data is upper 15 bits
const bool is_fault = (data & 0x0001) != 0;
const uint16_t data_temperature = data >> 1;
if (is_fault) {
#if MAX31865_DEBUGGING
uint8_t data_fault = 0;
_dev->read_registers(MAX31865_REG_FAULT_STATUS_READ, (uint8_t *)&data_fault, 1);
Debug("%d MAX31865 fault: 0x02X", _state.instance, data_fault);
#endif
// clear the fault
_dev->write_register(MAX31865_REG_CONFIG_WRITE, MAX31865_CONFIG_VALUE);
return;
}
// For a temperature range of -100 C to +100 C, a good approximation of
// temperature can be made with simple linearization. This equation gives
// 0 C error at 0C, -1.75 C error at -100 C, and -1.4 C error at +100 C
const float temperature = ((float)data_temperature/32.0f) - 256.0f;
#if MAX31865_DEBUGGING
Debug("%d MAX31865 %.2f C", _state.instance, temperature);
#endif
set_temperature(temperature);
}
#endif // AP_TEMPERATURE_SENSOR_MAX31865_ENABLED