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146 lines
3.5 KiB
C
146 lines
3.5 KiB
C
/**
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******************************************************************************
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*
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* @file pios_delay.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
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* Parts by Thorsten Klose (tk@midibox.org) (tk@midibox.org)
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* @brief Delay Functions
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* - Provides a micro-second granular delay using a TIM
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* @see The GNU Public License (GPL) Version 3
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* @defgroup PIOS_DELAY Delay Functions
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* @{
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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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/* Project Includes */
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#include "pios.h"
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#if defined(PIOS_INCLUDE_DELAY)
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/**
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* Initialises the Timer used by PIOS_DELAY functions<BR>
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* This is called from pios.c as part of the main() function
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* at system start up.
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* \return < 0 if initialisation failed
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*/
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#include <time.h>
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int32_t PIOS_DELAY_Init(void)
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{
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// stub
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/* No error */
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return 0;
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}
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/**
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* Waits for a specific number of uS<BR>
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* Example:<BR>
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* \code
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* // Wait for 500 uS
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* PIOS_DELAY_Wait_uS(500);
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* \endcode
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* \param[in] uS delay (1..65535 microseconds)
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* \return < 0 on errors
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*/
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int32_t PIOS_DELAY_WaituS(uint32_t uS)
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{
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static struct timespec wait, rest;
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wait.tv_sec = 0;
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wait.tv_nsec = 1000 * uS;
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while (nanosleep(&wait, &rest) != 0) {
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wait = rest;
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}
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/* No error */
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return 0;
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}
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/**
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* Waits for a specific number of mS<BR>
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* Example:<BR>
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* \code
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* // Wait for 500 mS
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* PIOS_DELAY_Wait_mS(500);
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* \endcode
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* \param[in] mS delay (1..65535 milliseconds)
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* \return < 0 on errors
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*/
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int32_t PIOS_DELAY_WaitmS(uint32_t mS)
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{
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// for(int i = 0; i < mS; i++) {
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// PIOS_DELAY_WaituS(1000);
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static struct timespec wait, rest;
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wait.tv_sec = mS / 1000;
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wait.tv_nsec = (mS % 1000) * 1000000;
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while (nanosleep(&wait, &rest) != 0) {
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wait = rest;
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}
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// }
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/* No error */
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return 0;
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}
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/**
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* @brief Query the Delay timer for the current uS
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* @return A microsecond value
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*/
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uint32_t PIOS_DELAY_GetuS()
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{
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static struct timespec current;
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clock_gettime(CLOCK_REALTIME, ¤t);
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return (current.tv_sec * 1000000) + (current.tv_nsec / 1000);
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}
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/**
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* @brief Calculate time in microseconds since a previous time
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* @param[in] t previous time
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* @return time in us since previous time t.
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*/
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uint32_t PIOS_DELAY_GetuSSince(uint32_t t)
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{
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return PIOS_DELAY_GetuS() - t;
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}
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/**
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* @brief Get the raw delay timer, useful for timing
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* @return Unitless value (uint32 wrap around)
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*/
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uint32_t PIOS_DELAY_GetRaw()
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{
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return PIOS_DELAY_GetuS();
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}
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/**
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* @brief Compare to raw times to and convert to us
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* @return A microsecond value
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*/
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uint32_t PIOS_DELAY_DiffuS(uint32_t raw)
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{
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return PIOS_DELAY_GetuS() - raw;
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}
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#endif /* if defined(PIOS_INCLUDE_DELAY) */
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