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/****************************************************************************
*
* Copyright (C) 2012 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file PPM input decoder.
*
* Works in conjunction with the HRT driver, exports a device node
* and a message queue (if message queues are enabled).
*
* Note that the device node supports both blocking and non-blocking
* opens, but actually never blocks. A nonblocking open will return
* EWOULDBLOCK if there has not been an update since the last read,
* while a blocking open will always return the most recent data.
*/
#include <sys/ioctl.h>
#define _PPM_INPUT_BASE 0x7600
/*
* Fetch the state of the PPM input detector.
*/
#define PPM_INPUT_STATUS _IOC(_PPM_INPUT_BASE, 0)
typedef enum {
PPM_STATUS_NO_SIGNAL = 0,
PPM_STATUS_SIGNAL_CURRENT = 1,
} ppm_input_status_t;
/*
* Fetch the number of channels decoded (only valid when PPM_STATUS_SIGNAL_CURRENT).
*/
#define PPM_INPUT_CHANNELS _IOC(_PPM_INPUT_BASE, 1)
typedef int ppm_input_channel_count_t;
/*
* Device node
*/
#define PPM_DEVICE_NODE "/dev/ppm_input"
/*
* Message queue; if message queues are supported, PPM input data is
* supplied to the queue when a frame is decoded.
*/
#ifndef CONFIG_DISABLE_MQUEUE
# define PPM_MESSAGE_QUEUE "ppm_input"
#endif
/*
* Private hook from the HRT driver to the PPM decoder.
*
* This function is called for every edge of the incoming PPM
* signal.
*
* @param reset If true, the decoder should be reset (e.g.)
* capture failure was detected.
* @param count The counter value at which the edge
* was captured.
*/
void ppm_input_decode(bool reset, uint16_t count);
/*
* PPM input initialisation function.
*
* If message queues are enabled, and mq_name is not NULL, received input
* is posted to the message queue as an array of 16-bit unsigned channel values.
*/
int ppm_input_init(const char *mq_name);
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