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             : /*
      17             :   backend driver for airspeed sensor from www.qio-tek.com
      18             :   I2C ASP5033 sensor
      19             :  */
      20             : 
      21             : #include "AP_Airspeed_ASP5033.h"
      22             : 
      23             : #if AP_AIRSPEED_ASP5033_ENABLED
      24             : 
      25             : #include <AP_HAL/I2CDevice.h>
      26             : 
      27             : extern const AP_HAL::HAL &hal;
      28             : 
      29             : #define ASP5033_I2C_ADDR_1     0x6C
      30             : #define ASP5033_I2C_ADDR_2     0x6D
      31             : #define REG_CMD                0x30
      32             : #define REG_PRESS_DATA         0x06
      33             : #define REG_TEMP_DATA          0x09
      34             : #define REG_PART_ID            0x01
      35             : #define REG_PART_ID_SET        0xa4
      36             : #define REG_SENSOR_READY       0x08
      37             : #define REG_WHOAMI_DEFAULT_ID  0X00
      38             : #define REG_WHOAMI_RECHECK_ID  0X66
      39             : #define CMD_MEASURE            0x0A
      40             : 
      41             : 
      42           0 : bool AP_Airspeed_ASP5033::init()
      43             : {
      44             :     // probe the sensor, supporting multiple possible I2C addresses
      45           0 :     const uint8_t addresses[] = { ASP5033_I2C_ADDR_1, ASP5033_I2C_ADDR_2 };
      46           0 :     for (uint8_t address : addresses) {
      47           0 :         dev = hal.i2c_mgr->get_device_ptr(get_bus(), address);
      48           0 :         if (!dev) {
      49           0 :             continue;
      50             :         }
      51             : 
      52           0 :         WITH_SEMAPHORE(dev->get_semaphore());
      53           0 :         dev->set_speed(AP_HAL::Device::SPEED_HIGH);
      54           0 :         dev->set_retries(2);
      55             : 
      56           0 :         if (!confirm_sensor_id()) {
      57           0 :             continue;
      58             :         }
      59             : 
      60           0 :         dev->set_device_type(uint8_t(DevType::ASP5033));
      61           0 :         set_bus_id(dev->get_bus_id());
      62             : 
      63           0 :         dev->register_periodic_callback(1000000UL/80U,
      64             :                                         FUNCTOR_BIND_MEMBER(&AP_Airspeed_ASP5033::timer, void));
      65           0 :         return true;
      66           0 :     }
      67             : 
      68             :     // not found
      69           0 :     return false;
      70             : }
      71             : 
      72             : /*
      73             :   this sensor has an unusual whoami scheme. The part_id is changeable
      74             :   via another register. We check the sensor by looking for the
      75             :   expected behaviour
      76             : */
      77           0 : bool AP_Airspeed_ASP5033::confirm_sensor_id(void)
      78             : {
      79             :     uint8_t part_id;
      80           0 :     if (!dev->read_registers(REG_PART_ID_SET, &part_id, 1) ||
      81           0 :         ( (part_id != REG_WHOAMI_DEFAULT_ID) && (part_id != REG_WHOAMI_RECHECK_ID) ) ) {
      82           0 :         return false;
      83             :     }
      84           0 :     if (!dev->write_register(REG_PART_ID_SET, REG_WHOAMI_RECHECK_ID)) {
      85           0 :         return false;
      86             :     }
      87           0 :     if (!dev->read_registers(REG_PART_ID, &part_id, 1) ||
      88           0 :         part_id != REG_WHOAMI_RECHECK_ID) {
      89           0 :         return false;
      90             :     }
      91           0 :     return true;
      92             : }
      93             : 
      94             : 
      95             : // read the data from the sensor
      96           0 : void AP_Airspeed_ASP5033::timer()
      97             : {
      98             :     // request a new measurement cycle begin
      99           0 :     dev->write_register(REG_CMD, CMD_MEASURE);
     100             : 
     101             :     uint8_t status;
     102           0 :     if (!dev->read_registers(REG_CMD, &status, 1) ||
     103           0 :         (status & REG_SENSOR_READY) == 0) {
     104             :         // no data ready
     105           0 :         return;
     106             :     }
     107             : 
     108             :     // read pressure and temperature as one block
     109             :     uint8_t data[5];
     110           0 :     if (!dev->read_registers(REG_PRESS_DATA, data, sizeof(data))) {
     111           0 :         return;
     112             :     }
     113             : 
     114             :     // ADC pressure is signed 24 bit
     115           0 :     int32_t press = (data[0]<<24) | (data[1]<<16) | (data[2]<<8);
     116             : 
     117             :     // convert back to 24 bit
     118           0 :     press >>= 8;
     119             : 
     120             :     // k is a shift based on the pressure range of the device. See
     121             :     // table in the datasheet
     122           0 :     constexpr uint8_t k = 7;
     123           0 :     constexpr float press_scale = 1.0 / (1U<<k);
     124             : 
     125             :     // temperature is 16 bit signed in units of 1/256 C
     126           0 :     const int16_t temp = (data[3]<<8) | data[4];
     127           0 :     constexpr float temp_scale = 1.0 / 256;
     128             : 
     129           0 :     WITH_SEMAPHORE(sem);
     130           0 :     press_sum += press * press_scale;
     131           0 :     temp_sum += temp * temp_scale;
     132           0 :     press_count++;
     133           0 :     temp_count++;
     134             : 
     135           0 :     last_sample_ms = AP_HAL::millis();
     136           0 : }
     137             : 
     138             : 
     139             : // return the current differential_pressure in Pascal
     140           0 : bool AP_Airspeed_ASP5033::get_differential_pressure(float &pressure)
     141             : {
     142           0 :     WITH_SEMAPHORE(sem);
     143             : 
     144           0 :     if (AP_HAL::millis() - last_sample_ms > 100) {
     145           0 :         return false;
     146             :     }
     147             : 
     148           0 :     if (press_count == 0) {
     149           0 :         pressure = last_pressure;
     150           0 :         return true;
     151             :     }
     152             : 
     153           0 :     last_pressure = pressure = press_sum / press_count;
     154             : 
     155           0 :     press_count = 0;
     156           0 :     press_sum = 0;
     157             : 
     158           0 :     return true;
     159           0 : }
     160             : 
     161             : // return the current temperature in degrees C, if available
     162           0 : bool AP_Airspeed_ASP5033::get_temperature(float &temperature)
     163             : {
     164           0 :     WITH_SEMAPHORE(sem);
     165             : 
     166           0 :     if (AP_HAL::millis() - last_sample_ms > 100) {
     167           0 :         return false;
     168             :     }
     169           0 :     if (temp_count == 0) {
     170           0 :         temperature = last_temperature;
     171           0 :         return true;
     172             :     }
     173             : 
     174           0 :     last_temperature = temperature = temp_sum / temp_count;
     175           0 :     temp_count = 0;
     176           0 :     temp_sum = 0;
     177             : 
     178           0 :     return true;
     179           0 : }
     180             : 
     181             : #endif