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265 lines
7.0 KiB
C
265 lines
7.0 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_SPEKTRUM Spektrum receiver functions
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* @brief Code to read Spektrum input
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* @{
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*
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* @file pios_spektrum.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
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* @brief USART commands. Inits USARTs, controls USARTs & Interrupt handlers. (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_spektrum_priv.h"
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#if defined(PIOS_INCLUDE_SPEKTRUM)
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/**
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* @Note Framesyncing:
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* The code resets the watchdog timer whenever a single byte is received, so what watchdog code
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* is never called if regularly getting bytes.
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* RTC timer is running @625Hz, supervisor timer has divider 5 so frame sync comes every 1/125Hz=8ms.
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* Good for both 11ms and 22ms framecycles
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*/
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/* Global Variables */
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/* Provide a RCVR driver */
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static int32_t PIOS_SPEKTRUM_Get(uint32_t rcvr_id, uint8_t channel);
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const struct pios_rcvr_driver pios_spektrum_rcvr_driver = {
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.read = PIOS_SPEKTRUM_Get,
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};
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/* Local Variables */
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static uint16_t CaptureValue[PIOS_SPEKTRUM_NUM_INPUTS],CaptureValueTemp[PIOS_SPEKTRUM_NUM_INPUTS];
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static uint8_t prev_byte = 0xFF, sync = 0, bytecount = 0, datalength=0, frame_error=0, byte_array[20] = { 0 };
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uint8_t sync_of = 0;
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uint16_t supv_timer=0;
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static void PIOS_SPEKTRUM_Supervisor(uint32_t spektrum_id);
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static bool PIOS_SPEKTRUM_Bind(const struct pios_spektrum_cfg * cfg);
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static int32_t PIOS_SPEKTRUM_Decode(uint8_t b);
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static uint16_t PIOS_SPEKTRUM_RxInCallback(uint32_t context, uint8_t * buf, uint16_t buf_len, uint16_t * headroom, bool * need_yield)
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{
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/* process byte(s) and clear receive timer */
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for (uint8_t i = 0; i < buf_len; i++) {
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PIOS_SPEKTRUM_Decode(buf[i]);
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supv_timer = 0;
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}
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/* Always signal that we can accept another byte */
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if (headroom) {
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*headroom = 1;
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}
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/* We never need a yield */
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*need_yield = false;
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/* Always indicate that all bytes were consumed */
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return (buf_len);
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}
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/**
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* Bind and Initialise Spektrum satellite receiver
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*/
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int32_t PIOS_SPEKTRUM_Init(uint32_t * spektrum_id, const struct pios_spektrum_cfg *cfg, const struct pios_com_driver * driver, uint32_t lower_id, bool bind)
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{
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// TODO: need setting flag for bind on next powerup
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if (bind) {
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PIOS_SPEKTRUM_Bind(cfg);
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}
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(driver->bind_rx_cb)(lower_id, PIOS_SPEKTRUM_RxInCallback, 0);
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if (!PIOS_RTC_RegisterTickCallback(PIOS_SPEKTRUM_Supervisor, 0)) {
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PIOS_DEBUG_Assert(0);
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}
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return (0);
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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_SPEKTRUM_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_SPEKTRUM_NUM_INPUTS) {
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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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* Spektrum bind function
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* \output true Successful bind
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* \output false Bind failed
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*/
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static bool PIOS_SPEKTRUM_Bind(const struct pios_spektrum_cfg * cfg)
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{
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#define BIND_PULSES 5
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GPIO_Init(cfg->bind.gpio, &cfg->bind.init);
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/* RX line, set high */
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GPIO_SetBits(cfg->bind.gpio, cfg->bind.init.GPIO_Pin);
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/* on CC works upto 140ms, I guess bind window is around 20-140ms after powerup */
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PIOS_DELAY_WaitmS(60);
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for (int i = 0; i < BIND_PULSES ; i++) {
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/* RX line, drive low for 120us */
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GPIO_ResetBits(cfg->bind.gpio, cfg->bind.init.GPIO_Pin);
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PIOS_DELAY_WaituS(120);
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/* RX line, drive high for 120us */
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GPIO_SetBits(cfg->bind.gpio, cfg->bind.init.GPIO_Pin);
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PIOS_DELAY_WaituS(120);
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}
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/* RX line, set input and wait for data, PIOS_SPEKTRUM_Init */
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return true;
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}
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/**
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* Decodes a byte
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* \param[in] b byte which should be spektrum decoded
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* \return 0 if no error
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* \return -1 if USART not available
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* \return -2 if buffer full (retry)
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* \note Applications shouldn't call these functions directly
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*/
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static int32_t PIOS_SPEKTRUM_Decode(uint8_t b)
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{
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static uint16_t channel = 0; /*, sync_word = 0;*/
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uint8_t channeln = 0, frame = 0;
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uint16_t data = 0;
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byte_array[bytecount] = b;
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bytecount++;
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if (sync == 0) {
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//sync_word = (prev_byte << 8) + b;
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#if 0
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/* maybe create object to show this data */
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if(bytecount==1)
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{
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/* record losscounter into channel8 */
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CaptureValueTemp[7]=b;
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/* instant write */
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CaptureValue[7]=b;
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}
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#endif
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/* Known sync bytes, 0x01, 0x02, 0x12, 0xb2 */
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/* 0xb2 DX8 3bind pulses only */
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if (bytecount == 2) {
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if ((b == 0x01) || (b == 0xb2)) {
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datalength=0; // 10bit
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//frames=1;
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sync = 1;
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bytecount = 2;
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}
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else if(b == 0x02) {
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datalength=0; // 10bit
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//frames=2;
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sync = 1;
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bytecount = 2;
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}
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else if(b == 0x12) {
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datalength=1; // 11bit
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//frames=2;
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sync = 1;
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bytecount = 2;
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}
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else
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{
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bytecount = 0;
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}
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}
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} else {
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if ((bytecount % 2) == 0) {
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channel = (prev_byte << 8) + b;
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frame = channel >> 15;
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channeln = (channel >> (10+datalength)) & 0x0F;
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data = channel & (0x03FF+(0x0400*datalength));
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if(channeln==0 && data<10) // discard frame if throttle misbehaves
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{
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frame_error=1;
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}
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if (channeln < PIOS_SPEKTRUM_NUM_INPUTS && !frame_error)
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CaptureValueTemp[channeln] = data;
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}
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}
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if (bytecount == 16) {
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//PIOS_COM_SendBufferNonBlocking(PIOS_COM_TELEM_RF,byte_array,16); //00 2c 58 84 b0 dc ff
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bytecount = 0;
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sync = 0;
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sync_of = 0;
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if (!frame_error)
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{
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for(int i=0;i<PIOS_SPEKTRUM_NUM_INPUTS;i++)
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{
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CaptureValue[i] = CaptureValueTemp[i];
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}
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}
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frame_error=0;
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}
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prev_byte = b;
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return 0;
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}
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/**
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*@brief This function is called between frames and when a spektrum word hasnt been decoded for too long
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*@brief clears the channel values
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*/
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static void PIOS_SPEKTRUM_Supervisor(uint32_t spektrum_id) {
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/* 625hz */
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supv_timer++;
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if(supv_timer > 4) {
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/* sync between frames */
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sync = 0;
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bytecount = 0;
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prev_byte = 0xFF;
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frame_error = 0;
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sync_of++;
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/* watchdog activated after 200ms silence */
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if (sync_of > 30) {
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/* signal lost */
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sync_of = 0;
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for (int i = 0; i < PIOS_SPEKTRUM_NUM_INPUTS; i++) {
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CaptureValue[i] = 0;
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CaptureValueTemp[i] = 0;
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}
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}
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supv_timer = 0;
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}
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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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