Enable flaps, avoid mode switch position

src/drivers/px4io/px4io.cpp

@@ -1274,7 +1274,7 @@ PX4IO::io_set_rc_config()
 
 	if ((ichan >= 0) && (ichan < (int)_max_rc_input)) {
 		/* use out of normal bounds index to indicate special channel */
-		input_map[ichan - 1] = 8;
+		input_map[ichan - 1] = PX4IO_P_RC_CONFIG_ASSIGNMENT_MODESWITCH;
 	}
 
 	/*

src/modules/px4iofirmware/controls.c

@@ -315,15 +315,12 @@ controls_tick() {
 						}
 					}
 
-					/* pick out override channel, indicated by mapping 8 (9 th channel, virtual) */
-					if (mapped == 8) {
-						rc_value_override = SIGNED_TO_REG(scaled);
-					} else {
-						/* normal channel */
 					r_rc_values[mapped] = SIGNED_TO_REG(scaled);
 					assigned_channels |= (1 << mapped);
-					}
 
+				} else if (mapped == PX4IO_P_RC_CONFIG_ASSIGNMENT_MODESWITCH) {
+					/* pick out override channel, indicated by special mapping */
+					rc_value_override = SIGNED_TO_REG(scaled);
 				}
 			}
 		}

src/modules/px4iofirmware/mixer.cpp

@@ -60,13 +60,6 @@ extern "C" {
  */
 #define FMU_INPUT_DROP_LIMIT_US		500000
 
-/* XXX need to move the RC_CHANNEL_FUNCTION out of rc_channels.h and into systemlib */
-#define ROLL     0
-#define PITCH    1
-#define YAW      2
-#define THROTTLE 3
-#define OVERRIDE 4
-
 /* current servo arm/disarm state */
 static bool mixer_servos_armed = false;
 static bool should_arm = false;

src/modules/px4iofirmware/protocol.h

@@ -246,6 +246,7 @@ enum {							/* DSM bind states */
 #define PX4IO_P_RC_CONFIG_MAX			2		/**< highest input value */
 #define PX4IO_P_RC_CONFIG_DEADZONE		3		/**< band around center that is ignored */
 #define PX4IO_P_RC_CONFIG_ASSIGNMENT		4		/**< mapped input value */
+#define PX4IO_P_RC_CONFIG_ASSIGNMENT_MODESWITCH	100		/**< magic value for mode switch */
 #define PX4IO_P_RC_CONFIG_OPTIONS		5		/**< channel options bitmask */
 #define PX4IO_P_RC_CONFIG_OPTIONS_ENABLED	(1 << 0)
 #define PX4IO_P_RC_CONFIG_OPTIONS_REVERSE	(1 << 1)

src/modules/px4iofirmware/registers.c

@@ -686,7 +686,8 @@ registers_set_one(uint8_t page, uint8_t offset, uint16_t value)
 
 				if (conf[PX4IO_P_RC_CONFIG_ASSIGNMENT] == UINT8_MAX) {
 					disabled = true;
-				} else if (conf[PX4IO_P_RC_CONFIG_ASSIGNMENT] >= PX4IO_RC_MAPPED_CONTROL_CHANNELS) {
+				} else if ((conf[PX4IO_P_RC_CONFIG_ASSIGNMENT] >= PX4IO_RC_MAPPED_CONTROL_CHANNELS) &&
+					   (conf[PX4IO_P_RC_CONFIG_ASSIGNMENT] != PX4IO_P_RC_CONFIG_ASSIGNMENT_MODESWITCH)) {
 					count++;
 				}