Line data    Source code

       1             : /*
       2             :  * Copyright (C) 2022  Kraus Hamdani Aerospace Inc. All rights reserved.
       3             :  *
       4             :  * This file is free software: you can redistribute it and/or modify it
       5             :  * under the terms of the GNU General Public License as published by the
       6             :  * Free Software Foundation, either version 3 of the License, or
       7             :  * (at your option) any later version.
       8             :  *
       9             :  * This file is distributed in the hope that it will be useful, but
      10             :  * WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
      12             :  * See the GNU General Public License for more details.
      13             :  *
      14             :  * You should have received a copy of the GNU General Public License along
      15             :  * with this program.  If not, see <http://www.gnu.org/licenses/>.
      16             :  *
      17             :  * Code by Tom Pittenger
      18             :  */
      19             : /*
      20             :     Implements I2C driver for Microchip MCP9600 and MCP9601 digital thermocouple EMF to Temperature converter
      21             : */
      22             : 
      23             : #include "AP_TemperatureSensor_MCP9600.h"
      24             : 
      25             : #if AP_TEMPERATURE_SENSOR_MCP9600_ENABLED
      26             : 
      27             : #include <stdio.h>
      28             : #include <AP_HAL/I2CDevice.h>
      29             : #include <AP_Math/AP_Math.h>
      30             : #include <GCS_MAVLink/GCS.h>
      31             : 
      32             : extern const AP_HAL::HAL &hal;
      33             : 
      34             : static const uint8_t MCP9600_CMD_HOT_JUNCT_TEMP     = 0x00;     // thermocoupler temp
      35             : //static const uint8_t MCP9600_CMD_JUNCT_TEMP_DELTA   = 0x01;
      36             : //static const uint8_t MCP9600_CMD_COLD_JUNCT_TEMP    = 0x02;     // ambient temp
      37             : //static const uint8_t MCP9600_CMD_RAW_DATA_ADC       = 0x03;
      38             : static const uint8_t MCP9600_CMD_STATUS             = 0x04;
      39             : static const uint8_t MCP9600_CMD_SENSOR_CFG         = 0x05;
      40             : //static const uint8_t MCP9600_CMD_DEVICE_CFG         = 0x06;
      41             : static const uint8_t MCP9600_CMD_DEVICE_ID_REV      = 0x20;     // to fetch WHOAMI
      42             : 
      43             : static const uint8_t MCP9600_CMD_STATUS_UPDATE_READY = 0x40;
      44             : 
      45             : static const uint8_t MCP9600_WHOAMI                 = 0x40;
      46             : static const uint8_t MCP9601_WHOAMI                 = 0x41;
      47             : 
      48             : 
      49             : #define MCP9600_ADDR_LOW        0x60    // ADDR pin pulled low
      50             : #define MCP9600_ADDR_HIGH       0x67    // ADDR pin pulled high
      51             : 
      52             : #define AP_TemperatureSensor_MCP9600_UPDATE_INTERVAL_MS     500
      53             : #define AP_TemperatureSensor_MCP9600_SCALE_FACTOR           (0.0625f)
      54             : 
      55             : #ifndef AP_TemperatureSensor_MCP9600_ADDR_DEFAULT
      56             :     #define AP_TemperatureSensor_MCP9600_ADDR_DEFAULT    MCP9600_ADDR_LOW
      57             : #endif
      58             : 
      59             : #ifndef AP_TemperatureSensor_MCP9600_Filter
      60             :     #define AP_TemperatureSensor_MCP9600_Filter         2   // can be values 0 through 7 where 0 is no filtering (fast) and 7 is lots of smoothing (very very slow)
      61             : #endif
      62             : 
      63           0 : void AP_TemperatureSensor_MCP9600::init()
      64             : {
      65           0 :     constexpr char name[] = "MCP9600";
      66             : 
      67           0 :     _dev = hal.i2c_mgr->get_device_ptr(_params.bus, _params.bus_address);
      68           0 :     if (!_dev) {
      69             :         // device not found
      70           0 :         return;
      71             :     }
      72             : 
      73           0 :     WITH_SEMAPHORE(_dev->get_semaphore());
      74             : 
      75           0 :     _dev->set_retries(10);
      76             : 
      77             :     uint8_t buf;
      78           0 :     if (!_dev->read_registers(MCP9600_CMD_DEVICE_ID_REV, &buf, 1)) {
      79           0 :         printf("%s failed to get WHOAMI", name);
      80           0 :         return;
      81             :     }
      82           0 :     if (buf != MCP9600_WHOAMI && buf != MCP9601_WHOAMI) {
      83           0 :         printf("%s Got wrong WHOAMI: detected 0x%2X", name, (unsigned)buf);
      84           0 :         return;
      85             :     }
      86           0 :     if (!set_config(ThermocoupleType::K, AP_TemperatureSensor_MCP9600_Filter)) {
      87           0 :         printf("%s unable to configure", name);
      88           0 :         return;
      89             :     }
      90             : 
      91             :     // lower retries for run
      92           0 :     _dev->set_retries(3);
      93             : 
      94             :     /* Request 5Hz update */
      95           0 :     _dev->register_periodic_callback(200 * AP_USEC_PER_MSEC,
      96             :                                      FUNCTOR_BIND_MEMBER(&AP_TemperatureSensor_MCP9600::_timer, void));
      97           0 : }
      98             : 
      99           0 : void AP_TemperatureSensor_MCP9600::_timer()
     100             : {
     101             :     float temperature;
     102           0 :     if (read_temperature(temperature)) {
     103           0 :         set_temperature(temperature);
     104             :     }
     105           0 : }
     106             : 
     107           0 : bool AP_TemperatureSensor_MCP9600::set_config(const ThermocoupleType thermoType, const uint8_t filter)
     108             : {
     109           0 :     const uint8_t data = (uint8_t)thermoType << 4 | (filter & 0x7);
     110           0 :     if (!_dev->write_register(MCP9600_CMD_SENSOR_CFG, data)) {
     111           0 :         return false;
     112             :     }
     113           0 :     return true;
     114             : }
     115             : 
     116           0 : bool AP_TemperatureSensor_MCP9600::read_temperature(float &temperature)
     117             : {
     118             :     // confirm new temperature is available and then read it
     119             : 
     120             :     // First, read STATUS register:
     121             :     uint8_t data[2];
     122           0 :     if (!_dev->read_registers(MCP9600_CMD_STATUS, data, 1)) {
     123           0 :         return false;
     124             :     }
     125             :     // check UPDATE bit for new temperature data ready:
     126           0 :     if ((data[0] & MCP9600_CMD_STATUS_UPDATE_READY) == 0) {
     127           0 :         return false;
     128             :     }
     129             :     // read temperature:
     130           0 :     if (!_dev->read_registers(MCP9600_CMD_HOT_JUNCT_TEMP, data, 2)) {
     131           0 :         return false;
     132             :     }
     133             :     // clear update bit:
     134           0 :     if (!_dev->write_register(0x04, data[0] & ~MCP9600_CMD_STATUS_UPDATE_READY)) {
     135           0 :         return false;
     136             :     }
     137             : 
     138             :     // scale temperature:
     139           0 :     temperature = int16_t(UINT16_VALUE(data[0], data[1])) * AP_TemperatureSensor_MCP9600_SCALE_FACTOR;
     140             : 
     141           0 :     return true;
     142             : }
     143             : #endif // AP_TEMPERATURE_SENSOR_MCP9600_ENABLED
     144             :