Inital commit

2026-06-14 19:48:37 +02:00
commit cd7d411332
30 changed files with 1645 additions and 0 deletions
@@ -0,0 +1,65 @@
+#pragma once
+#include <stdint.h>
+#include <stddef.h>
+
+/* CRSF frame header byte */
+#define CEL_CRSF_FRAME_HEADER 0xC8
+
+/* CRSF device addresses */
+#define CEL_CRSF_ADDRESS_FC_BROADCAST      0x00
+#define CEL_CRSF_ADDRESS_FC                0x10
+#define CEL_CRSF_ADDRESS_TBS_GROUND_STATION 0x80
+#define CEL_CRSF_ADDRESS_CUSTOM_MODULE     0xEA
+#define CEL_CRSF_ADDRESS_RC_DEVICE         0xDD
+#define CEL_CRSF_ADDRESS_GPS               0xEC
+#define CEL_CRSF_ADDRESS_FLIGHT_CONTROLLER 0xED
+
+/* CRSF frame types */
+typedef enum {
+    CEL_CRSF_FRAMETYPE_PACKET_LINK_TELEMETRY    = 0x02,
+    CEL_CRSF_FRAMETYPE_RC_CHANNELS_PACKED       = 0x01,
+    CEL_CRSF_FRAMETYPE_GPS                      = 0x02,
+    CEL_CRSF_FRAMETYPE_HEARTBEAT                = 0x03,
+    CEL_CRSF_FRAMETYPE_VERSION                  = 0x04,
+    CEL_CRSF_FRAMETYPE_PARAMETER_SETTINGS_ENTRY = 0x05,
+    CEL_CRSF_FRAMETYPE_PARAMETER_READ           = 0x06,
+    CEL_CRSF_FRAMETYPE_PARAMETER_WRITE          = 0x07,
+    CEL_CRSF_FRAMETYPE_DEVICE_INFO              = 0x08,
+    CEL_CRSF_FRAMETYPE_PARAMETER_LIST           = 0x09,
+    CEL_CRSF_FRAMETYPE_RC_CHANNELS_RAW          = 0x16,
+    CEL_CRSF_FRAMETYPE_MSP_READ                 = 0x17,
+    CEL_CRSF_FRAMETYPE_MSP_WRITE                = 0x18,
+    CEL_CRSF_FRAMETYPE_CURR_VOLTAGE_TEMP        = 0x1E,
+    CEL_CRSF_FRAMETYPE_BATTERY_SENSOR           = 0x1F,
+    CEL_CRSF_FRAMETYPE_COMPRESSED_SENSORS       = 0x28,
+    CEL_CRSF_FRAMETYPE_ARM                      = 0x0D,
+    CEL_CRSF_FRAMETYPE_SETTING                  = 0x9E,
+    CEL_CRSF_FRAMETYPE_SUPERBOX                 = 0xA0,
+    CEL_CRSF_FRAMETYPE_DEVICE_SUPERBOX          = 0xA1,
+} cel_crsf_frame_type;
+
+/* Parsed CRSF frame */
+typedef struct {
+    uint8_t  destination;
+    uint8_t  source;
+    uint8_t  type;
+    uint8_t  size;
+    uint8_t  payload[255];
+    uint8_t  crc;
+} cel_crsf_frame;
+
+/* CRC8 calculation over CRSF frame data (CCITT poly 0x07) */
+uint8_t cel_crsf_crc(uint8_t const* data, size_t len);
+
+/* Validate CRC of a CRSF frame (header already stripped, starts at dest addr) */
+int cel_crsf_frame_validate(cel_crsf_frame const* frame);
+
+/* Parse a raw buffer into a cel_crsf_frame. Returns 0 on success, -1 on error.
+   buf should start with 0xC8 header. */
+int cel_crsf_frame_parse(cel_crsf_frame* frame, uint8_t const* buf, size_t len);
+
+/* Build a CRSF frame into dst buffer. Returns total bytes written.
+   dst must have space for at least 5 + size bytes (header, addr, src, type,
+   size byte, payload, crc). */
+size_t cel_crsf_frame_build(uint8_t* dst, uint8_t destination, uint8_t source,
+                            uint8_t type, uint8_t const* payload, uint8_t size);