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LibrePilot/flight/PiOS/STM32F10x/pios_ppm.c

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/**
******************************************************************************
*
* @file pios_ppm.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief PPM Input functions
* @see The GNU Public License (GPL) Version 3
* @defgroup PIOS_PPM PPM Input Functions
* @{
*
*****************************************************************************/
/*
* 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
*/
/* Project Includes */
#include "pios.h"
#if defined(PIOS_INCLUDE_PPM)
/* Local Variables */
static TIM_ICInitTypeDef TIM_ICInitStructure;
static uint8_t PulseIndex;
static uint8_t CaptureState;
static uint16_t RiseValue;
static uint16_t FallValue;
static uint32_t CaptureValue[PIOS_PPM_NUM_INPUTS];
static uint8_t SupervisorState = 0;
static uint32_t CapCounter[PIOS_PPM_NUM_INPUTS];
static uint32_t CapCounterPrev[PIOS_PPM_NUM_INPUTS];
/**
* Initialises all the LED's
*/
void PIOS_PPM_Init(void)
{
/* Flush counter variables */
int32_t i;
PulseIndex = 0;
CaptureState = 0;
RiseValue = 0;
FallValue = 0;
for(i = 0; i < PIOS_PPM_NUM_INPUTS; i++) {
CaptureValue[i] = 0;
}
/* Setup RCC */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);
/* Enable timer interrupts */
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_InitStructure.NVIC_IRQChannel = PIOS_PPM_TIM_IRQ;
NVIC_Init(&NVIC_InitStructure);
/* Configure input pins */
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStructure.GPIO_Pin = PIOS_PPM_GPIO_PIN;
GPIO_Init(PIOS_PPM_GPIO_PORT, &GPIO_InitStructure);
/* Configure timer for input capture */
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM_ICInitStructure.TIM_ICFilter = 0x0;
TIM_ICInitStructure.TIM_Channel = PIOS_PPM_TIM_CHANNEL;
TIM_ICInit(PIOS_PPM_TIM_PORT, &TIM_ICInitStructure);
/* Configure timer clocks */
TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = 0xFFFF;
TIM_TimeBaseStructure.TIM_Prescaler = (PIOS_MASTER_CLOCK / 1000000) - 1;
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_InternalClockConfig(PIOS_PPM_TIM_PORT);
TIM_TimeBaseInit(PIOS_PPM_TIM_PORT, &TIM_TimeBaseStructure);
/* Enable the Capture Compare Interrupt Request */
TIM_ITConfig(PIOS_PPM_TIM_PORT, PIOS_PPM_TIM_CCR, ENABLE);
/* Enable timers */
TIM_Cmd(PIOS_PPM_TIM, ENABLE);
/* Supervisor Setup */
#if (PIOS_PPM_SUPV_ENABLED)
/* Flush counter variables */
for(i = 0; i < PIOS_PPM_NUM_INPUTS; i++) {
CapCounter[i] = 0;
}
for(i = 0; i < PIOS_PPM_NUM_INPUTS; i++) {
CapCounterPrev[i] = 0;
}
/* Enable timer clock */
PIOS_PPM_SUPV_TIMER_RCC_FUNC;
/* Configure interrupts */
NVIC_InitStructure.NVIC_IRQChannel = PIOS_PPM_SUPV_IRQ_CHANNEL;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* Time base configuration */
TIM_TimeBaseStructInit(&TIM_TimeBaseStructure);
TIM_TimeBaseStructure.TIM_Period = ((1000000 / PIOS_PPM_SUPV_HZ) - 1);
TIM_TimeBaseStructure.TIM_Prescaler = (PIOS_MASTER_CLOCK / 1000000) - 1; /* For 1 uS accuracy */
TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(PIOS_PPM_SUPV_TIMER, &TIM_TimeBaseStructure);
/* Enable the CC2 Interrupt Request */
TIM_ITConfig(PIOS_PPM_SUPV_TIMER, TIM_IT_Update, ENABLE);
/* Clear update pending flag */
TIM_ClearFlag(TIM2, TIM_FLAG_Update);
/* Enable counter */
TIM_Cmd(PIOS_PPM_SUPV_TIMER, ENABLE);
#endif
/* Setup local variable which stays in this scope */
/* Doing this here and using a local variable saves doing it in the ISR */
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM_ICInitStructure.TIM_ICFilter = 0x0;
}
/**
* Get the value of an input channel
* \param[in] Channel Number of the channel desired
* \output -1 Channel not available
* \output >0 Channel value
*/
int32_t PIOS_PPM_Get(int8_t Channel)
{
/* Return error if channel not available */
if(Channel >= PIOS_PPM_NUM_INPUTS) {
return -1;
}
return CaptureValue[Channel];
}
/**
* Handle TIM1 global interrupt request
* Some work and testing still needed, need to detect start of frame and decode pulses
*
*/
void TIM1_CC_IRQHandler(void)
{
/* Do this as it's more efficient */
if(TIM_GetITStatus(PIOS_PWM_CH1_TIM_PORT, RECEIVER1_CCR) == SET) {
if(CaptureState == 0) {
RiseValue = TIM_GetCapture2(PIOS_PWM_CH1_TIM_PORT);
} else {
FallValue = TIM_GetCapture2(PIOS_PWM_CH1_TIM_PORT);
}
}
/* Clear TIM3 Capture compare interrupt pending bit */
TIM_ClearITPendingBit(PIOS_PWM_CH1_TIM_PORT, RECEIVER1_CCR);
/* Simple rise or fall state machine */
if(CaptureState == 0) {
/* Switch states */
CaptureState = 1;
/* Switch polarity of input capture */
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Falling;
TIM_ICInitStructure.TIM_Channel = RECEIVER1_CH;
TIM_ICInit(PIOS_PWM_CH1_TIM_PORT, &TIM_ICInitStructure);
} else {
/* Capture computation */
if (FallValue > RiseValue) {
//need to change
CaptureValue[0] = (FallValue - RiseValue);
} else {
//need to change
CaptureValue[0] = ((0xFFFF - RiseValue) + FallValue);
}
/* Switch states */
CaptureState = 0;
/* Increase supervisor counter */
CapCounter[0]++;
/* Switch polarity of input capture */
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStructure.TIM_Channel = RECEIVER1_CH;
TIM_ICInit(PIOS_PWM_CH1_TIM_PORT, &TIM_ICInitStructure);
}
}
/**
* This function handles TIM3 global interrupt request.
*/
PIOS_PPM_SUPV_IRQ_FUNC
{
/* Clear timer interrupt pending bit */
TIM_ClearITPendingBit(PIOS_PPM_SUPV_TIMER, TIM_IT_Update);
/* Simple state machine */
if(SupervisorState == 0) {
/* Save this states values */
for(int32_t i = 0; i < PIOS_PPM_NUM_INPUTS; i++) {
CapCounterPrev[i] = CapCounter[i];
}
/* Move to next state */
SupervisorState = 1;
} else {
/* See what channels have been updated */
for(int32_t i = 0; i < PIOS_PPM_NUM_INPUTS; i++) {
if(CapCounter[i] == CapCounterPrev[i]) {
CaptureValue[i] = 0;
}
}
/* Move to next state */
SupervisorState = 0;
}
}
#endif