/** ****************************************************************************** * @addtogroup OpenPilotModules OpenPilot Modules * @{ * @addtogroup AltitudeModule Altitude Module * @brief Communicate with BMP085 and update @ref BaroAltitude "BaroAltitude UAV Object" * @{ * * @file altitude.c * @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010. * @brief Altitude module, handles temperature and pressure readings from BMP085 * * @see The GNU Public License (GPL) Version 3 * *****************************************************************************/ /* * 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, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /** * Output object: BaroAltitude * * This module will periodically update the value of the BaroAltitude object. * */ #include "openpilot.h" #include "baroaltitude.h" // object that will be updated by the module // Private constants #define STACK_SIZE configMINIMAL_STACK_SIZE #define TASK_PRIORITY (tskIDLE_PRIORITY+3) //#define UPDATE_PERIOD 100 #define UPDATE_PERIOD 25 // Private types // Private variables static xTaskHandle taskHandle; // down sampling variables #define alt_ds_size 4 static int32_t alt_ds_temp = 0; static int32_t alt_ds_pres = 0; static int alt_ds_count = 0; // Private functions static void altitudeTask(void *parameters); /** * Initialise the module, called on startup * \returns 0 on success or -1 if initialisation failed */ int32_t AltitudeInitialize() { // Start main task xTaskCreate(altitudeTask, (signed char *)"Altitude", STACK_SIZE, NULL, TASK_PRIORITY, &taskHandle); TaskMonitorAdd(TASKINFO_RUNNING_ALTITUDE, taskHandle); // init down-sampling data alt_ds_temp = 0; alt_ds_pres = 0; alt_ds_count = 0; return 0; } /** * Module thread, should not return. */ static void altitudeTask(void *parameters) { BaroAltitudeData data; portTickType lastSysTime; PIOS_BMP085_Init(); // Main task loop lastSysTime = xTaskGetTickCount(); while (1) { // Update the temperature data PIOS_BMP085_StartADC(TemperatureConv); xSemaphoreTake(PIOS_BMP085_EOC, portMAX_DELAY); PIOS_BMP085_ReadADC(); alt_ds_temp += PIOS_BMP085_GetTemperature(); // Update the pressure data PIOS_BMP085_StartADC(PressureConv); xSemaphoreTake(PIOS_BMP085_EOC, portMAX_DELAY); PIOS_BMP085_ReadADC(); alt_ds_pres += PIOS_BMP085_GetPressure(); if (++alt_ds_count >= alt_ds_size) { alt_ds_count = 0; // Convert from 1/10ths of degC to degC data.Temperature = alt_ds_temp / (10.0 * alt_ds_size); alt_ds_temp = 0; // Convert from Pa to kPa data.Pressure = alt_ds_pres / (1000.0f * alt_ds_size); alt_ds_pres = 0; // Compute the current altitude (all pressures in kPa) data.Altitude = 44330.0 * (1.0 - powf((data.Pressure / (BMP085_P0 / 1000.0)), (1.0 / 5.255))); // Update the AltitudeActual UAVObject BaroAltitudeSet(&data); } // Delay until it is time to read the next sample vTaskDelayUntil(&lastSysTime, UPDATE_PERIOD / portTICK_RATE_MS); } } /** * @} * @} */