More protocol decoding skeleton code

src/lib/rc/module.mk

@@ -0,0 +1,40 @@
+############################################################################
+#
+#   Copyright (c) 2014 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.
+#
+############################################################################
+
+#
+# Yuntec ST24 transmitter protocol decoder
+#
+
+SRCS		 =	st24.c
+
+MAXOPTIMIZATION	 = -Os

src/lib/rc/st24.c

@@ -64,3 +64,6 @@ uint8_t st24_common_crc8(uint8_t *ptr, uint8_t len)
 
 	return (crc);
 }
+
+
+uint8_t st24_decode(uint8_t byte, uint8_t *rssi, uint8_t* rx_count, uint16_t *channels, uint16_t max_chan_count)

src/lib/rc/st24.h

@@ -137,4 +137,16 @@ typedef struct {
  * @param len number of bytes to accumulate in the checksum
  * @return the checksum of these bytes over len
  */
-__EXPORT uint8_t st24_common_crc8(uint8_t *ptr, uint8_t len);
+uint8_t st24_common_crc8(uint8_t *ptr, uint8_t len);
+
+/**
+ * Decoder for ST24 protocol
+ *
+ * @param byte current char to read
+ * @param rssi pointer to a byte where the RSSI value is written back to
+ * @param rx_count pointer to a byte where the receive count of packets signce last wireless frame is written back to
+ * @param channels pointer to a datastructure of size max_chan_count where channel values (12 bit) are written back to
+ * @param max_chan_count maximum channels to decode - if more channels are decoded, the last n are skipped and success (0) is returned
+ * @return 0 for success (a decoded packet), 1 for no packet yet (accumulating), 3 for out of sync, 4 for checksum error
+ */
+__EXPORT uint8_t st24_decode(uint8_t byte, uint8_t *rssi, uint8_t* rx_count, uint16_t *channels, uint16_t max_chan_count);