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125 lines
3.6 KiB
C
125 lines
3.6 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_RFM22B_RCVR RFM22B Receiver Input Functions
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* @brief Code to output the PPM signal from the RFM22B
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* @{
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*
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* @file pios_rfm22b_rcvr.c
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* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2012.
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* @brief Implements a receiver interface to the RFM22B device
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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_RFM22B_RCVR
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#include "pios_rfm22b_priv.h"
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/* Provide a RCVR driver */
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static int32_t PIOS_RFM22B_RCVR_Get(uint32_t rcvr_id, uint8_t channel);
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static void PIOS_RFM22B_RCVR_Supervisor(uint32_t rcvr_id);
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const struct pios_rcvr_driver pios_rfm22b_rcvr_driver = {
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.read = PIOS_RFM22B_RCVR_Get,
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};
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/**
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* Initialize the receiver.
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*
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* @param[in] rfm22b_dev The receiver ID.
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* @return < 0 on failure.
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*/
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int32_t PIOS_RFM22B_RCVR_Init(uint32_t rcvr_id)
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{
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struct pios_rfm22b_dev *rfm22b_dev = (struct pios_rfm22b_dev *)rcvr_id;
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if (!PIOS_RFM22B_Validate(rfm22b_dev)) {
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return -1;
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}
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// Initialize
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for (uint8_t i = 0; i < PIOS_RFM22B_RCVR_MAX_CHANNELS; ++i) {
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rfm22b_dev->ppm_channel[i] = PIOS_RCVR_TIMEOUT;
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}
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rfm22b_dev->ppm_supv_timer = 0;
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// Register the failsafe timer callback.
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if (!PIOS_RTC_RegisterTickCallback(PIOS_RFM22B_RCVR_Supervisor, rcvr_id)) {
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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 a channel from the receiver.
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*
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* @param[in] rcvr_id The receiver ID.
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* @return The channel value, or -1 on failure.
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*/
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static int32_t PIOS_RFM22B_RCVR_Get(uint32_t rcvr_id, uint8_t channel)
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{
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struct pios_rfm22b_dev *rfm22b_dev = (struct pios_rfm22b_dev *)rcvr_id;
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if (!PIOS_RFM22B_Validate(rfm22b_dev)) {
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return -1;
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}
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if (channel >= GCSRECEIVER_CHANNEL_NUMELEM) {
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/* channel is out of range */
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return -1;
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}
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return rfm22b_dev->ppm_channel[channel];
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}
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/**
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* The supervisor function that ensures that the data is current.
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*
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* @param[in] rcvr_id The receiver ID.
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*/
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static void PIOS_RFM22B_RCVR_Supervisor(uint32_t rcvr_id) {
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struct pios_rfm22b_dev *rfm22b_dev = (struct pios_rfm22b_dev *)rcvr_id;
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if (!PIOS_RFM22B_Validate(rfm22b_dev)) {
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return;
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}
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// RTC runs at 625Hz.
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if (++(rfm22b_dev->ppm_supv_timer) < (PIOS_RFM22B_RCVR_TIMEOUT_MS * 1000 / 625)) {
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return;
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}
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rfm22b_dev->ppm_supv_timer = 0;
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// Have we received fresh values since the last update?
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if (!rfm22b_dev->ppm_fresh) {
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for (uint8_t i = 0; i < PIOS_RFM22B_RCVR_MAX_CHANNELS; ++i) {
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rfm22b_dev->ppm_channel[i] = 0;
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}
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}
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rfm22b_dev->ppm_fresh = false;
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}
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#endif /* PIOS_INCLUDE_RFM22B_RCVR */
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/**
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* @}
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* @}
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*/
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