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authorJulian Oes <julian@oes.ch>2013-05-17 11:24:02 +0200
committerJulian Oes <julian@oes.ch>2013-05-17 11:24:02 +0200
commitf5c157e74df12a0cb36b7d27cdad9828d96cc534 (patch)
tree3f758990921a7b52df8afe5131a8298b1141b6f4 /src/modules/systemlib/ppm_decode.h
parent80e8eeab2931e79e31adb17c93f5794e666c5763 (diff)
parentfa816d0fd65da461fd5bf8803cf00caebaf23c5c (diff)
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Merge remote-tracking branch 'upstream/master' into new_state_machine
Conflicts: src/drivers/px4io/px4io.cpp src/modules/commander/commander.c src/modules/commander/state_machine_helper.c
Diffstat (limited to 'src/modules/systemlib/ppm_decode.h')
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1 files changed, 85 insertions, 0 deletions
diff --git a/src/modules/systemlib/ppm_decode.h b/src/modules/systemlib/ppm_decode.h
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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_decode.h
+ *
+ * PPM input decoder.
+ */
+
+#pragma once
+
+#include <drivers/drv_hrt.h>
+
+/**
+ * Maximum number of channels that we will decode.
+ */
+#define PPM_MAX_CHANNELS 12
+
+/* PPM input nominal min/max values */
+#define PPM_MIN 1000
+#define PPM_MAX 2000
+#define PPM_MID ((PPM_MIN + PPM_MAX) / 2)
+
+__BEGIN_DECLS
+
+/*
+ * PPM decoder state
+ */
+__EXPORT extern uint16_t ppm_buffer[PPM_MAX_CHANNELS]; /**< decoded PPM channel values */
+__EXPORT extern unsigned ppm_decoded_channels; /**< count of decoded channels */
+__EXPORT extern hrt_abstime ppm_last_valid_decode; /**< timestamp of the last valid decode */
+
+/**
+ * Initialise the PPM input decoder.
+ *
+ * @param count_max The maximum value of the counter passed to
+ * ppm_input_decode, used to determine how to
+ * handle counter wrap.
+ */
+__EXPORT void ppm_input_init(unsigned count_max);
+
+/**
+ * Inform the decoder of an edge on the PPM input.
+ *
+ * This function can be registered with the HRT as the PPM edge handler.
+ *
+ * @param reset If set, the edge detector has missed one or
+ * more edges and the decoder needs to be reset.
+ * @param count A microsecond timestamp corresponding to the
+ * edge, in the range 0-count_max. This value
+ * is expected to wrap.
+ */
+__EXPORT void ppm_input_decode(bool reset, unsigned count);
+
+__END_DECLS \ No newline at end of file