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https://bitbucket.org/librepilot/librepilot.git
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11c568ec50
Move update of capture values to start of new frame. Fix an issue with setting channels to invalid.
316 lines
9.2 KiB
C
316 lines
9.2 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_PPM PPM Input Functions
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* @brief Code to measure PPM input and seperate into channels
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* @{
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*
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* @file pios_ppm.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
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* @brief PPM 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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/* Project Includes */
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#include "pios.h"
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#include "pios_ppm_priv.h"
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#if defined(PIOS_INCLUDE_PPM)
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/* Provide a RCVR driver */
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static int32_t PIOS_PPM_Get(uint32_t rcvr_id, uint8_t channel);
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const struct pios_rcvr_driver pios_ppm_rcvr_driver = {
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.read = PIOS_PPM_Get,
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};
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#define PIOS_PPM_IN_MIN_NUM_CHANNELS 4
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#define PIOS_PPM_IN_MAX_NUM_CHANNELS 8
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#define PIOS_PPM_STABLE_CHANNEL_COUNT 25 // frames
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#define PIOS_PPM_IN_MIN_SYNC_PULSE_US 7000 // microseconds
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#define PIOS_PPM_IN_MIN_CHANNEL_PULSE_US 750 // microseconds
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#define PIOS_PPM_IN_MAX_CHANNEL_PULSE_US 2400 // microseconds
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#define PIOS_PPM_INPUT_INVALID 0
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/* Local Variables */
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static TIM_ICInitTypeDef TIM_ICInitStructure;
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static uint8_t PulseIndex;
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static uint32_t PreviousTime;
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static uint32_t CurrentTime;
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static uint32_t DeltaTime;
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static uint32_t CaptureValue[PIOS_PPM_IN_MAX_NUM_CHANNELS];
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static uint32_t CaptureValueNewFrame[PIOS_PPM_IN_MAX_NUM_CHANNELS];
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static uint32_t LargeCounter;
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static int8_t NumChannels;
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static int8_t NumChannelsPrev;
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static uint8_t NumChannelCounter;
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static uint8_t supv_timer = 0;
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static bool Tracking;
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static bool Fresh;
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static void PIOS_PPM_Supervisor(uint32_t ppm_id);
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void PIOS_PPM_Init(void)
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{
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/* Flush counter variables */
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int32_t i;
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PulseIndex = 0;
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PreviousTime = 0;
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CurrentTime = 0;
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DeltaTime = 0;
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LargeCounter = 0;
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NumChannels = -1;
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NumChannelsPrev = -1;
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NumChannelCounter = 0;
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Tracking = FALSE;
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Fresh = FALSE;
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for (i = 0; i < PIOS_PPM_IN_MAX_NUM_CHANNELS; i++) {
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CaptureValue[i] = 0;
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CaptureValueNewFrame[i] = 0;
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}
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NVIC_InitTypeDef NVIC_InitStructure = pios_ppm_cfg.irq.init;
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/* Enable appropriate clock to timer module */
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switch((int32_t) pios_ppm_cfg.timer) {
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case (int32_t)TIM1:
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NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;
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RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
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break;
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case (int32_t)TIM2:
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NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);
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break;
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case (int32_t)TIM3:
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NVIC_InitStructure.NVIC_IRQChannel = TIM3_IRQn;
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
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break;
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case (int32_t)TIM4:
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NVIC_InitStructure.NVIC_IRQChannel = TIM4_IRQn;
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
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break;
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#ifdef STM32F10X_HD
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case (int32_t)TIM5:
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NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn;
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE);
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break;
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case (int32_t)TIM6:
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NVIC_InitStructure.NVIC_IRQChannel = TIM6_IRQn;
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM6, ENABLE);
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break;
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case (int32_t)TIM7:
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NVIC_InitStructure.NVIC_IRQChannel = TIM7_IRQn;
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RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM7, ENABLE);
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break;
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case (int32_t)TIM8:
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NVIC_InitStructure.NVIC_IRQChannel = TIM8_CC_IRQn;
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RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM8, ENABLE);
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break;
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#endif
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}
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/* Enable timer interrupts */
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NVIC_Init(&NVIC_InitStructure);
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/* Configure input pins */
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GPIO_InitTypeDef GPIO_InitStructure = pios_ppm_cfg.gpio_init;
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GPIO_Init(pios_ppm_cfg.port, &GPIO_InitStructure);
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/* Configure timer for input capture */
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TIM_ICInitStructure = pios_ppm_cfg.tim_ic_init;
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TIM_ICInit(pios_ppm_cfg.timer, &TIM_ICInitStructure);
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/* Configure timer clocks */
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TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure = pios_ppm_cfg.tim_base_init;
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TIM_InternalClockConfig(pios_ppm_cfg.timer);
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TIM_TimeBaseInit(pios_ppm_cfg.timer, &TIM_TimeBaseStructure);
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/* Enable the Capture Compare Interrupt Request */
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TIM_ITConfig(pios_ppm_cfg.timer, pios_ppm_cfg.ccr | TIM_IT_Update, ENABLE);
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/* Enable timers */
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TIM_Cmd(pios_ppm_cfg.timer, ENABLE);
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/* Setup local variable which stays in this scope */
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/* Doing this here and using a local variable saves doing it in the ISR */
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TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
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TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
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TIM_ICInitStructure.TIM_ICFilter = 0x0;
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if (!PIOS_RTC_RegisterTickCallback(PIOS_PPM_Supervisor, 0)) {
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PIOS_DEBUG_Assert(0);
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}
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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
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* \output -1 Channel not available
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* \output >0 Channel value
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*/
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static int32_t PIOS_PPM_Get(uint32_t rcvr_id, uint8_t channel)
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{
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/* Return error if channel not available */
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if (channel > PIOS_PPM_IN_MAX_NUM_CHANNELS) {
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return -1;
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}
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return CaptureValue[channel];
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}
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/**
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* Handle TIMx global interrupt request
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* Some work and testing still needed, need to detect start of frame and decode pulses
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*
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*/
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void PIOS_PPM_irq_handler(void)
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{
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/* Timer Overflow Interrupt
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* The time between timer overflows must be greater than the PPM
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* frame period. If a full frame has not decoded in the between timer
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* overflows then capture values should be cleared.
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*/
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if (TIM_GetITStatus(pios_ppm_cfg.timer, TIM_IT_Update) == SET) {
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/* Clear TIMx overflow interrupt pending bit */
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TIM_ClearITPendingBit(pios_ppm_cfg.timer, TIM_IT_Update);
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/* If sharing a timer with a servo output the ARR register will
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be set according to the PWM period. When timer reaches the
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ARR value a timer overflow interrupt will fire. We use the
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interrupt accumulate a 32-bit timer. */
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LargeCounter = LargeCounter + pios_ppm_cfg.timer->ARR;
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}
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/* Signal edge interrupt */
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if (TIM_GetITStatus(pios_ppm_cfg.timer, pios_ppm_cfg.ccr) == SET) {
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PreviousTime = CurrentTime;
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switch((int32_t) pios_ppm_cfg.ccr) {
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case (int32_t)TIM_IT_CC1:
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CurrentTime = TIM_GetCapture1(pios_ppm_cfg.timer);
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break;
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case (int32_t)TIM_IT_CC2:
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CurrentTime = TIM_GetCapture2(pios_ppm_cfg.timer);
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break;
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case (int32_t)TIM_IT_CC3:
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CurrentTime = TIM_GetCapture3(pios_ppm_cfg.timer);
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break;
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case (int32_t)TIM_IT_CC4:
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CurrentTime = TIM_GetCapture4(pios_ppm_cfg.timer);
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break;
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}
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/* Clear TIMx Capture compare interrupt pending bit */
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TIM_ClearITPendingBit(pios_ppm_cfg.timer, pios_ppm_cfg.ccr);
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/* Convert to 32-bit timer result */
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CurrentTime = CurrentTime + LargeCounter;
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/* Capture computation */
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DeltaTime = CurrentTime - PreviousTime;
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PreviousTime = CurrentTime;
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/* Sync pulse detection */
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if (DeltaTime > PIOS_PPM_IN_MIN_SYNC_PULSE_US) {
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if (PulseIndex == NumChannelsPrevFrame
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&& PulseIndex >= PIOS_PPM_IN_MIN_NUM_CHANNELS
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&& PulseIndex <= PIOS_PPM_IN_MAX_NUM_CHANNELS)
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{
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/* If we see n simultaneous frames of the same
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number of channels we save it as our frame size */
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if (NumChannelCounter < PIOS_PPM_STABLE_CHANNEL_COUNT)
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NumChannelCounter++;
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else
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NumChannels = PulseIndex;
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} else {
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NumChannelCounter = 0;
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}
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/* Check if the last frame was well formed */
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if (PulseIndex == NumChannels && Tracking) {
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/* The last frame was well formed */
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for (uint32_t i = 0; i < NumChannels; i++) {
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CaptureValue[i] = CaptureValueNewFrame[i];
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}
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for (uint32_t i = NumChannels;
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i < PIOS_PPM_IN_MAX_NUM_CHANNELS; i++) {
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CaptureValue[i] = 0;
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}
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}
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Fresh = TRUE;
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Tracking = TRUE;
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NumChannelsPrevFrame = PulseIndex;
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PulseIndex = 0;
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/* We rely on the supervisor to set CaptureValue to invalid
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if no valid frame is found otherwise we ride over it */
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} else if (Tracking) {
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/* Valid pulse duration 0.75 to 2.5 ms*/
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if (DeltaTime > PIOS_PPM_IN_MIN_CHANNEL_PULSE_US
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&& DeltaTime < PIOS_PPM_IN_MAX_CHANNEL_PULSE_US
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&& PulseIndex < PIOS_PPM_IN_MAX_NUM_INPUTS) {
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CaptureValueNewFrame[PulseIndex] = DeltaTime;
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PulseIndex++;
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} else {
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/* Not a valid pulse duration */
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Tracking = FALSE;
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for (uint32_t i = 0; i < PIOS_PPM_IN_MAX_NUM_CHANNELS ; i++) {
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CaptureValueNewFrame[i] = PIOS_PPM_INPUT_INVALID;
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}
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}
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}
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}
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}
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static void PIOS_PPM_Supervisor(uint32_t ppm_id) {
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/*
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* RTC runs at 625Hz so divide down the base rate so
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* that this loop runs at 25Hz.
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*/
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if(++supv_timer < 25) {
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return;
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}
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supv_timer = 0;
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if (!Fresh) {
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Tracking = FALSE;
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for (int32_t i = 0; i < PIOS_PPM_IN_MAX_NUM_CHANNELS ; i++) {
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CaptureValue[i] = PIOS_PPM_INPUT_INVALID;
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CaptureValueNewFrame[i] = PIOS_PPM_INPUT_INVALID;
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}
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}
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Fresh = FALSE;
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}
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#endif
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/**
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* @}
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* @}
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*/
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