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This module reads from the BMP085 pressure sensor. It periodically updates the pressure (kPa) and temperature (C) as well as the calculated altitude (m). git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@640 ebee16cc-31ac-478f-84a7-5cbb03baadba
110 lines
3.1 KiB
C
110 lines
3.1 KiB
C
/**
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******************************************************************************
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*
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* @file altitude.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
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* @brief Altitude module, handles temperature and pressure readings from BMP085
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*
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* @see The GNU Public License (GPL) Version 3
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*
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*****************************************************************************/
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/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/**
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* Output object: AltitudeActual
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*
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* This module will periodically update the value of the AltitudeActual object.
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*
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*/
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#include "openpilot.h"
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#include "altitudeactual.h" // object that will be updated by the module
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// Private constants
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#define STACK_SIZE configMINIMAL_STACK_SIZE
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#define TASK_PRIORITY (tskIDLE_PRIORITY+3)
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// Private types
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// Private variables
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static xTaskHandle taskHandle;
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// Private functions
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static void altitudeTask(void* parameters);
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/**
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* Initialise the module, called on startup
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* \returns 0 on success or -1 if initialisation failed
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*/
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int32_t AltitudeInitialize()
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{
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// Start main task
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xTaskCreate(altitudeTask, (signed char*)"Altitude", STACK_SIZE, NULL, TASK_PRIORITY, &taskHandle);
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return 0;
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}
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/**
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* Module thread, should not return.
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*/
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static void altitudeTask(void* parameters)
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{
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AltitudeActualData data;
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portTickType lastSysTime;
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PIOS_BMP085_Init();
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// Main task loop
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lastSysTime = xTaskGetTickCount();
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while (1)
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{
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// Get the object data
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AltitudeActualGet(&data);
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// Update the temperature data
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PIOS_BMP085_StartADC(TemperatureConv);
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#if 0
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xSemaphoreTake(PIOS_BMP085_EOC, portMAX_DELAY);
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#else
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vTaskDelay( 5 / portTICK_RATE_MS );
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#endif
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PIOS_BMP085_ReadADC();
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// Convert from 1/10ths of degC to degC
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data.Temperature = PIOS_BMP085_GetTemperature() / 10.0;
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// Update the pressure data
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PIOS_BMP085_StartADC(PressureConv);
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#if 0
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xSemaphoreTake(PIOS_BMP085_EOC, portMAX_DELAY);
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#else
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vTaskDelay( 26 / portTICK_RATE_MS );
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#endif
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PIOS_BMP085_ReadADC();
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// Convert from Pa to kPa
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data.Pressure = PIOS_BMP085_GetPressure() / 1000.0;
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// Compute the current altitude (all pressures in kPa)
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data.Altitude = 44330.0 * (1.0 - powf((data.Pressure/ (BMP085_P0 / 1000.0)), (1.0/5.255)));
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// Update the AltitudeActual UAVObject
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AltitudeActualSet(&data);
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// Delay until it is time to read the next sample
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vTaskDelayUntil(&lastSysTime, 1000 / portTICK_RATE_MS );
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}
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}
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