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LibrePilot/flight/PiOS/STM32F10x/pios_spektrum.c

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/**
******************************************************************************
* @addtogroup PIOS PIOS Core hardware abstraction layer
* @{
* @addtogroup PIOS_SPEKTRUM Spektrum receiver functions
* @brief Code to read Spektrum input
* @{
*
* @file pios_spektrum.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* Parts by Thorsten Klose (tk@midibox.org) (tk@midibox.org)
* @brief USART commands. Inits USARTs, controls USARTs & Interrupt handlers. (STM32 dependent)
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* 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"
#include "pios_spektrum_priv.h"
#if defined(PIOS_INCLUDE_SPEKTRUM)
#if defined(PIOS_INCLUDE_PWM) || defined(PIOS_INCLUDE_SBUS)
#error "Both SPEKTRUM and either of PWM or SBUS inputs defined, choose only one"
#endif
#if defined(PIOS_COM_AUX)
#error "AUX com cannot be used with SPEKTRUM"
#endif
/**
* @Note Framesyncing:
* The code resets the watchdog timer whenever a single byte is received, so what watchdog code
* is never called if regularly getting bytes.
* RTC timer is running @625Hz, supervisor timer has divider 5 so frame sync comes every 1/125Hz=8ms.
* Good for both 11ms and 22ms framecycles
*/
/* Global Variables */
/* Local Variables */
static uint16_t CaptureValue[12],CaptureValueTemp[12];
static uint8_t prev_byte = 0xFF, sync = 0, bytecount = 0, datalength=0, frame_error=0, byte_array[20] = { 0 };
uint8_t sync_of = 0;
uint16_t supv_timer=0;
/**
* Bind and Initialise Spektrum satellite receiver
*/
void PIOS_SPEKTRUM_Init(void)
{
// TODO: need setting flag for bind on next powerup
if (0) {
PIOS_SPEKTRUM_Bind();
}
/* Init RTC supervisor timer interrupt */
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = RTC_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = PIOS_IRQ_PRIO_MID;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* Init RTC clock */
PIOS_RTC_Init();
}
/**
* Get the value of an input channel
* \param[in] Channel Number of the channel desired
* \output -1 Channel not available
* \output >0 Channel value
*/
int16_t PIOS_SPEKTRUM_Get(int8_t Channel)
{
/* Return error if channel not available */
if (Channel >= 12) {
return -1;
}
return CaptureValue[Channel];
}
/**
* Spektrum bind function
* \output 1 Successful bind
* \output 0 Bind failed
* \note Applications shouldn't call these functions directly
*/
uint8_t PIOS_SPEKTRUM_Bind(void)
{
GPIO_InitTypeDef GPIO_InitStructure = pios_spektrum_cfg.gpio_init;
GPIO_InitStructure.GPIO_Pin = pios_spektrum_cfg.pin;
GPIO_Init(pios_spektrum_cfg.port, &GPIO_InitStructure);
pios_spektrum_cfg.port->BRR = pios_spektrum_cfg.pin;
//PIOS_DELAY_WaitmS(75);
/* RX line, drive high for 10us */
pios_spektrum_cfg.port->BSRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(10);
/* RX line, drive low for 120us */
pios_spektrum_cfg.port->BRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, drive high for 120us */
pios_spektrum_cfg.port->BSRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, drive low for 120us */
pios_spektrum_cfg.port->BRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, drive high for 120us */
pios_spektrum_cfg.port->BSRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, drive low for 120us */
pios_spektrum_cfg.port->BRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, drive high for 120us */
pios_spektrum_cfg.port->BSRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, drive low for 120us */
pios_spektrum_cfg.port->BRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, drive high for 120us */
pios_spektrum_cfg.port->BSRR = pios_spektrum_cfg.pin;
PIOS_DELAY_WaituS(120);
/* RX line, set input and wait for data, PIOS_SPEKTRUM_Init */
return 1;
}
/**
* Decodes a byte
* \param[in] b byte which should be spektrum decoded
* \return 0 if no error
* \return -1 if USART not available
* \return -2 if buffer full (retry)
* \note Applications shouldn't call these functions directly
*/
int32_t PIOS_SPEKTRUM_Decode(uint8_t b)
{
static uint16_t channel = 0; /*, sync_word = 0;*/
uint8_t channeln = 0, frame = 0;
uint16_t data = 0;
byte_array[bytecount] = b;
bytecount++;
if (sync == 0) {
//sync_word = (prev_byte << 8) + b;
#if 0
/* maybe create object to show this data */
if(bytecount==1)
{
/* record losscounter into channel8 */
CaptureValueTemp[7]=b;
/* instant write */
CaptureValue[7]=b;
}
#endif
/* Known sync bytes, 0x01, 0x02, 0x12 */
if (bytecount == 2) {
if (b == 0x01) {
datalength=0; // 10bit
//frames=1;
sync = 1;
bytecount = 2;
}
else if(b == 0x02) {
datalength=0; // 10bit
//frames=2;
sync = 1;
bytecount = 2;
}
else if(b == 0x12) {
datalength=1; // 11bit
//frames=2;
sync = 1;
bytecount = 2;
}
else
{
bytecount = 0;
}
}
} else {
if ((bytecount % 2) == 0) {
channel = (prev_byte << 8) + b;
frame = channel >> 15;
channeln = (channel >> (10+datalength)) & 0x0F;
data = channel & (0x03FF+(0x0400*datalength));
if(channeln==0 && data<10) // discard frame if throttle misbehaves
{
frame_error=1;
}
if (channeln < 12 && !frame_error)
CaptureValueTemp[channeln] = data;
}
}
if (bytecount == 16) {
//PIOS_COM_SendBufferNonBlocking(PIOS_COM_TELEM_RF,byte_array,16); //00 2c 58 84 b0 dc ff
bytecount = 0;
sync = 0;
sync_of = 0;
if (!frame_error)
{
for(int i=0;i<12;i++)
{
CaptureValue[i] = CaptureValueTemp[i];
}
}
frame_error=0;
}
prev_byte = b;
return 0;
}
/* Interrupt handler for USART */
void SPEKTRUM_IRQHandler(uint32_t usart_id) {
/* by always reading DR after SR make sure to clear any error interrupts */
volatile uint16_t sr = pios_spektrum_cfg.pios_usart_spektrum_cfg->regs->SR;
volatile uint8_t b = pios_spektrum_cfg.pios_usart_spektrum_cfg->regs->DR;
/* check if RXNE flag is set */
if (sr & USART_SR_RXNE) {
if (PIOS_SPEKTRUM_Decode(b) < 0) {
/* Here we could add some error handling */
}
}
if (sr & USART_SR_TXE) { // check if TXE flag is set
/* Disable TXE interrupt (TXEIE=0) */
USART_ITConfig(pios_spektrum_cfg.pios_usart_spektrum_cfg->regs, USART_IT_TXE, DISABLE);
}
/* byte arrived so clear "watchdog" timer */
supv_timer=0;
}
/**
*@brief This function is called between frames and when a spektrum word hasnt been decoded for too long
*@brief clears the channel values
*/
void PIOS_SPEKTRUM_irq_handler() {
/* 125hz */
supv_timer++;
if(supv_timer > 5) {
/* sync between frames */
sync = 0;
bytecount = 0;
prev_byte = 0xFF;
frame_error = 0;
sync_of++;
/* watchdog activated after 100ms silence */
if (sync_of > 12) {
/* signal lost */
sync_of = 0;
for (int i = 0; i < 12; i++) {
CaptureValue[i] = 0;
CaptureValueTemp[i] = 0;
}
}
supv_timer = 0;
}
}
#endif
/**
* @}
* @}
*/