Another take on Spektrum/DSM frame decoding, based on more careful examination of the relevant docs.

apps/px4io/protocol.h

@@ -41,11 +41,6 @@
 
 #pragma once
 
-/*
- * XXX MUST BE KEPT IN SYNC WITH THE VERSION IN PX4FMU UNTIL
- * TREES ARE MERGED.
- */
-
 #define PX4IO_OUTPUT_CHANNELS	8
 #define PX4IO_INPUT_CHANNELS	12
 #define PX4IO_RELAY_CHANNELS	4
@@ -69,8 +64,8 @@ struct px4io_config {
 
 	uint8_t		serial_rx_mode;
 #define RX_MODE_PPM_ONLY	0
-#define RX_MODE_SPEKTRUM_6	1
-#define RX_MODE_SPEKTRUM_7	2
+#define RX_MODE_DSM_10BIT	1
+#define RX_MODE_DSM_11BIT	2
 #define RX_MODE_FUTABA_SBUS	3
 };