Line data    Source code

       1             : /*
       2             :    This program is free software: you can redistribute it and/or modify
       3             :    it under the terms of the GNU General Public License as published by
       4             :    the Free Software Foundation, either version 3 of the License, or
       5             :    (at your option) any later version.
       6             : 
       7             :    This program is distributed in the hope that it will be useful,
       8             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
       9             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      10             :    GNU General Public License for more details.
      11             : 
      12             :    You should have received a copy of the GNU General Public License
      13             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.
      14             :  */
      15             : 
      16             : #include "AP_TemperatureSensor_TMP119.h"
      17             : 
      18             : #if AP_TEMPERATURE_SENSOR_TMP119_ENABLED
      19             : 
      20             : #include <AP_HAL/AP_HAL.h>
      21             : #include <AP_HAL/I2CDevice.h>
      22             : #include <AP_Math/AP_Math.h>
      23             : 
      24             : extern const AP_HAL::HAL &hal;
      25             : 
      26             : // register addresses
      27             : #define TMP119_REG_TEMP         0x00    // temperature result register
      28             : #define TMP119_REG_CONFIG       0x01    // configuration register
      29             : #define TMP119_REG_DEVICE_ID    0x0F    // device ID register
      30             : 
      31             : #define TMP119_DEVICE_ID        0x2117  // value reported in the device ID register
      32             : 
      33             : // each LSB of the temperature register is 7.8125 m degrees C
      34             : #define TMP119_TEMP_PER_LSB     0.0078125f
      35             : 
      36             : // configuration register fields
      37             : #define TMP119_CONFIG_MOD_CONTINUOUS    (0x0 << 10) // continuous conversion mode
      38             : #define TMP119_CONFIG_CONV_15MS         (0x0 << 7)  // 15.5ms conversion cycle
      39             : #define TMP119_CONFIG_AVG_NONE          (0x0 << 5)  // no averaging
      40             : 
      41             : // continuous conversion, no averaging, shortest (15.5ms / ~64Hz) conversion
      42             : // cycle so that a fresh sample is available for every 20Hz poll
      43             : #define TMP119_CONFIG_VALUE     (TMP119_CONFIG_MOD_CONTINUOUS | \
      44             :                                  TMP119_CONFIG_CONV_15MS | \
      45             :                                  TMP119_CONFIG_AVG_NONE)
      46             : 
      47           0 : void AP_TemperatureSensor_TMP119::init()
      48             : {
      49           0 :     _params.bus_address.set_default(AP_TEMPERATURE_SENSOR_TMP119_DEFAULT_I2C_ADDR);
      50             : 
      51           0 :     _dev = hal.i2c_mgr->get_device_ptr(_params.bus, _params.bus_address);
      52           0 :     if (!_dev) {
      53           0 :         return;
      54             :     }
      55             : 
      56           0 :     WITH_SEMAPHORE(_dev->get_semaphore());
      57             : 
      58           0 :     _dev->set_retries(10);
      59             : 
      60             :     // confirm we are talking to a TMP119
      61             :     uint16_t device_id;
      62           0 :     if (!read_registers(TMP119_REG_DEVICE_ID, device_id) || (device_id != TMP119_DEVICE_ID)) {
      63           0 :         return;
      64             :     }
      65             : 
      66             :     // configure for continuous conversion with no averaging and the shortest
      67             :     // conversion cycle so a new measurement is ready for each 20Hz poll. The
      68             :     // power-up default is a 1Hz cycle with 8x averaging, which is too slow.
      69           0 :     if (!write_register(TMP119_REG_CONFIG, TMP119_CONFIG_VALUE)) {
      70           0 :         return;
      71             :     }
      72             : 
      73             :     // lower retries for run
      74           0 :     _dev->set_retries(3);
      75             : 
      76             :     // poll the temperature register at 20Hz
      77           0 :     _dev->register_periodic_callback(50 * AP_USEC_PER_MSEC,
      78             :                                      FUNCTOR_BIND_MEMBER(&AP_TemperatureSensor_TMP119::_timer, void));
      79           0 : }
      80             : 
      81           0 : void AP_TemperatureSensor_TMP119::_timer(void)
      82             : {
      83             :     uint16_t raw;
      84           0 :     if (!read_registers(TMP119_REG_TEMP, raw)) {
      85           0 :         return;
      86             :     }
      87             : 
      88             :     // the temperature register holds a signed 16-bit value
      89           0 :     const float temp = (int16_t)raw * TMP119_TEMP_PER_LSB;
      90           0 :     set_temperature(temp);
      91             : }
      92             : 
      93           0 : bool AP_TemperatureSensor_TMP119::read_registers(uint8_t reg, uint16_t &value) const
      94             : {
      95             :     uint8_t val[2];
      96           0 :     if (!_dev->transfer(&reg, 1, val, sizeof(val))) {
      97           0 :         return false;
      98             :     }
      99           0 :     value = UINT16_VALUE(val[0], val[1]);
     100           0 :     return true;
     101             : }
     102             : 
     103           0 : bool AP_TemperatureSensor_TMP119::write_register(uint8_t reg, uint16_t value) const
     104             : {
     105             :     // registers are 16-bit big-endian
     106           0 :     uint8_t buf[3] { reg, uint8_t(value >> 8), uint8_t(value & 0xFF) };
     107           0 :     return _dev->transfer(buf, sizeof(buf), nullptr, 0);
     108             : }
     109             : 
     110             : #endif // AP_TEMPERATURE_SENSOR_TMP119_ENABLED