Added initial bits for ST24 decoding

2026-11-02 03:21:35 +08:00 · 2014-07-10 13:14:39 +02:00
parent 58cae259e4
commit af4d5c0a3c
2 changed files with 206 additions and 0 deletions
@@ -0,0 +1,66 @@
+/****************************************************************************
+ *
+ *   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.
+ *
+ ****************************************************************************/
+
+/*
+ * @file st24.h
+ *
+ * RC protocol implementation for Yuneec ST24 transmitter.
+ *
+ * @author Lorenz Meier <lm@inf.ethz.ch>
+ */
+
+uint8_t st24_common_crc8(uint8_t *ptr, uint8_t len)
+{
+	uint8_t i, crc ;
+	crc = 0;
+
+	while (len--) {
+		for (i = 0x80; i != 0; i >>= 1) {
+			if ((crc & 0x80) != 0) {
+				crc <<= 1;
+				crc ^= 0x07;
+
+			} else {
+				crc <<= 1;
+			}
+
+			if ((*ptr & i) != 0) {
+				crc ^= 0x07;
+			}
+		}
+
+		ptr++;
+	}
+
+	return (crc);
+}