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https://bitbucket.org/librepilot/librepilot.git
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290 lines
8.9 KiB
C
290 lines
8.9 KiB
C
/**
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******************************************************************************
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* @addtogroup PIOS PIOS Core hardware abstraction layer
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* @{
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* @addtogroup PIOS_PWM PWM Input Functions
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* @brief Code to measure with PWM input
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* @{
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*
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* @file pios_pwm.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
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* @brief PWM Input functions (STM32 dependent)
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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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#include "pios.h"
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#ifdef PIOS_INCLUDE_PWM
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#include "pios_pwm_priv.h"
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/* Provide a RCVR driver */
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static int32_t PIOS_PWM_Get(uint32_t rcvr_id, uint8_t channel);
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const struct pios_rcvr_driver pios_pwm_rcvr_driver = {
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.read = PIOS_PWM_Get,
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};
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/* Local Variables */
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/* 100 ms timeout without updates on channels */
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static const uint32_t PWM_SUPERVISOR_TIMEOUT = 100000;
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enum pios_pwm_dev_magic {
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PIOS_PWM_DEV_MAGIC = 0xab30293c,
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};
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struct pios_pwm_dev {
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enum pios_pwm_dev_magic magic;
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const struct pios_pwm_cfg *cfg;
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uint8_t CaptureState[PIOS_PWM_NUM_INPUTS];
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uint16_t RiseValue[PIOS_PWM_NUM_INPUTS];
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uint16_t FallValue[PIOS_PWM_NUM_INPUTS];
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uint32_t CaptureValue[PIOS_PWM_NUM_INPUTS];
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uint32_t CapCounter[PIOS_PWM_NUM_INPUTS];
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uint32_t us_since_update[PIOS_PWM_NUM_INPUTS];
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};
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static bool PIOS_PWM_validate(struct pios_pwm_dev *pwm_dev)
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{
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return pwm_dev->magic == PIOS_PWM_DEV_MAGIC;
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}
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#if defined(PIOS_INCLUDE_FREERTOS)
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static struct pios_pwm_dev *PIOS_PWM_alloc(void)
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{
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struct pios_pwm_dev *pwm_dev;
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pwm_dev = (struct pios_pwm_dev *)pios_malloc(sizeof(*pwm_dev));
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if (!pwm_dev) {
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return NULL;
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}
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pwm_dev->magic = PIOS_PWM_DEV_MAGIC;
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return pwm_dev;
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}
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#else
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static struct pios_pwm_dev pios_pwm_devs[PIOS_PWM_MAX_DEVS];
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static uint8_t pios_pwm_num_devs;
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static struct pios_pwm_dev *PIOS_PWM_alloc(void)
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{
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struct pios_pwm_dev *pwm_dev;
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if (pios_pwm_num_devs >= PIOS_PWM_MAX_DEVS) {
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return NULL;
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}
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pwm_dev = &pios_pwm_devs[pios_pwm_num_devs++];
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pwm_dev->magic = PIOS_PWM_DEV_MAGIC;
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return pwm_dev;
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}
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#endif /* if defined(PIOS_INCLUDE_FREERTOS) */
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static void PIOS_PWM_tim_overflow_cb(uint32_t id, uint32_t context, uint8_t channel, uint16_t count);
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static void PIOS_PWM_tim_edge_cb(uint32_t id, uint32_t context, uint8_t channel, uint16_t count);
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static const struct pios_tim_callbacks tim_callbacks = {
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.overflow = PIOS_PWM_tim_overflow_cb,
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.edge = PIOS_PWM_tim_edge_cb,
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};
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/**
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* Initialises all the pins
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*/
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int32_t PIOS_PWM_Init(uint32_t *pwm_id, const struct pios_pwm_cfg *cfg)
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{
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PIOS_DEBUG_Assert(pwm_id);
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PIOS_DEBUG_Assert(cfg);
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struct pios_pwm_dev *pwm_dev;
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pwm_dev = (struct pios_pwm_dev *)PIOS_PWM_alloc();
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if (!pwm_dev) {
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goto out_fail;
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}
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/* Bind the configuration to the device instance */
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pwm_dev->cfg = cfg;
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for (uint8_t i = 0; i < PIOS_PWM_NUM_INPUTS; i++) {
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/* Flush counter variables */
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pwm_dev->CaptureState[i] = 0;
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pwm_dev->RiseValue[i] = 0;
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pwm_dev->FallValue[i] = 0;
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pwm_dev->CaptureValue[i] = PIOS_RCVR_TIMEOUT;
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}
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uint32_t tim_id;
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if (PIOS_TIM_InitChannels(&tim_id, cfg->channels, cfg->num_channels, &tim_callbacks, (uint32_t)pwm_dev)) {
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return -1;
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}
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/* Configure the channels to be in capture/compare mode */
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for (uint8_t i = 0; i < cfg->num_channels; i++) {
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const struct pios_tim_channel *chan = &cfg->channels[i];
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/* Configure timer for input capture */
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TIM_ICInitTypeDef TIM_ICInitStructure = cfg->tim_ic_init;
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TIM_ICInitStructure.TIM_Channel = chan->timer_chan;
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TIM_ICInit(chan->timer, &TIM_ICInitStructure);
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/* Enable the Capture Compare Interrupt Request */
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switch (chan->timer_chan) {
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case TIM_Channel_1:
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TIM_ITConfig(chan->timer, TIM_IT_CC1, ENABLE);
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break;
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case TIM_Channel_2:
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TIM_ITConfig(chan->timer, TIM_IT_CC2, ENABLE);
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break;
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case TIM_Channel_3:
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TIM_ITConfig(chan->timer, TIM_IT_CC3, ENABLE);
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break;
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case TIM_Channel_4:
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TIM_ITConfig(chan->timer, TIM_IT_CC4, ENABLE);
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break;
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}
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// Need the update event for that timer to detect timeouts
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TIM_ITConfig(chan->timer, TIM_IT_Update, ENABLE);
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}
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*pwm_id = (uint32_t)pwm_dev;
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return 0;
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out_fail:
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return -1;
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}
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/**
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* Get the value of an input channel
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* \param[in] channel Number of the channel desired (zero based)
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* \output PIOS_RCVR_INVALID channel not available
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* \output PIOS_RCVR_TIMEOUT failsafe condition or missing receiver
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* \output >=0 channel value
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*/
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static int32_t PIOS_PWM_Get(uint32_t rcvr_id, uint8_t channel)
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{
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struct pios_pwm_dev *pwm_dev = (struct pios_pwm_dev *)rcvr_id;
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if (!PIOS_PWM_validate(pwm_dev)) {
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/* Invalid device specified */
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return PIOS_RCVR_INVALID;
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}
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if (channel >= PIOS_PWM_NUM_INPUTS) {
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/* Channel out of range */
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return PIOS_RCVR_INVALID;
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}
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return pwm_dev->CaptureValue[channel];
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}
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static void PIOS_PWM_tim_overflow_cb(__attribute__((unused)) uint32_t tim_id, uint32_t context, uint8_t channel, uint16_t count)
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{
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struct pios_pwm_dev *pwm_dev = (struct pios_pwm_dev *)context;
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if (!PIOS_PWM_validate(pwm_dev)) {
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/* Invalid device specified */
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return;
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}
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if (channel >= pwm_dev->cfg->num_channels) {
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/* Channel out of range */
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return;
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}
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if (!pwm_dev->CaptureState[channel]) {
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return;
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}
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pwm_dev->us_since_update[channel] += count;
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if (pwm_dev->us_since_update[channel] >= PWM_SUPERVISOR_TIMEOUT) {
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pwm_dev->CaptureState[channel] = 0;
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pwm_dev->RiseValue[channel] = 0;
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pwm_dev->FallValue[channel] = 0;
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pwm_dev->CaptureValue[channel] = PIOS_RCVR_TIMEOUT;
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pwm_dev->us_since_update[channel] = 0;
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}
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}
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static void PIOS_PWM_tim_edge_cb(__attribute__((unused)) uint32_t tim_id, uint32_t context, uint8_t chan_idx, uint16_t count)
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{
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/* Recover our device context */
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struct pios_pwm_dev *pwm_dev = (struct pios_pwm_dev *)context;
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if (!PIOS_PWM_validate(pwm_dev)) {
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/* Invalid device specified */
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return;
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}
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if (chan_idx >= pwm_dev->cfg->num_channels) {
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/* Channel out of range */
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return;
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}
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const struct pios_tim_channel *chan = &pwm_dev->cfg->channels[chan_idx];
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if (pwm_dev->CaptureState[chan_idx] == 0) {
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pwm_dev->RiseValue[chan_idx] = count;
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pwm_dev->us_since_update[chan_idx] = 0;
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} else {
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pwm_dev->FallValue[chan_idx] = count;
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}
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// flip state machine and capture value here
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/* Simple rise or fall state machine */
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TIM_ICInitTypeDef TIM_ICInitStructure = pwm_dev->cfg->tim_ic_init;
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if (pwm_dev->CaptureState[chan_idx] == 0) {
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/* Switch states */
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pwm_dev->CaptureState[chan_idx] = 1;
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/* Switch polarity of input capture */
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TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;
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TIM_ICInitStructure.TIM_Channel = chan->timer_chan;
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TIM_ICInit(chan->timer, &TIM_ICInitStructure);
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} else {
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uint32_t value = 0;
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/* Capture computation */
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value = pwm_dev->us_since_update[chan_idx] + (pwm_dev->FallValue[chan_idx] - pwm_dev->RiseValue[chan_idx]);
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// From time to time glitches happens. Most of the observed case are related to missing or spurious overflows
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// happening when they are triggered very close each other.
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// The following workaround prevents them to cause troubles by filtering unacceptable values
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if (PIOS_PWM_VALID_RANGE_MAX > value && PIOS_PWM_VALID_RANGE_MIN < value) {
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pwm_dev->CaptureValue[chan_idx] = value;
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}
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/* Switch states */
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pwm_dev->CaptureState[chan_idx] = 0;
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pwm_dev->us_since_update[chan_idx] = 0;
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/* Increase supervisor counter */
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pwm_dev->CapCounter[chan_idx]++;
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/* Switch polarity of input capture */
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TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
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TIM_ICInitStructure.TIM_Channel = chan->timer_chan;
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TIM_ICInit(chan->timer, &TIM_ICInitStructure);
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}
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}
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#endif /* PIOS_INCLUDE_PWM */
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/**
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* @}
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* @}
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*/
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