AP_RCProtocol: allow selection of protocols for pulse input

libraries/AP_RCProtocol/AP_RCProtocol.cpp

@@ -56,13 +56,11 @@ void AP_RCProtocol::process_pulse(uint32_t width_s0, uint32_t width_s1)
     }
 
     // otherwise scan all protocols
-    rcprotocol_t last_protocol = AP_RCProtocol::NONE;
-#ifdef HAL_RCIN_PULSE_PPM_ONLY
-    // only uses pulses for PPM on this board, using process_byte() for
-    // other protocols
-    last_protocol = (rcprotocol_t)1;
-#endif
-    for (uint8_t i = 0; i < last_protocol; i++) {
+    for (uint8_t i = 0; i < AP_RCProtocol::NONE; i++) {
+        if (_disabled_for_pulses & (1U << i)) {
+            // this protocol is disabled for pulse input
+            continue;
+        }
         if (backend[i] != nullptr) {
             backend[i]->process_pulse(width_s0, width_s1);
             if (backend[i]->new_input()) {

libraries/AP_RCProtocol/AP_RCProtocol.h

@@ -45,6 +45,11 @@ public:
     }
     void process_pulse(uint32_t width_s0, uint32_t width_s1);
     void process_byte(uint8_t byte, uint32_t baudrate);
+
+    void disable_for_pulses(enum rcprotocol_t protocol) {
+        _disabled_for_pulses |= (1U<<(uint8_t)protocol);
+    }
+
     enum rcprotocol_t protocol_detected()
     {
         return _detected_protocol;
@@ -61,6 +66,7 @@ public:
 
 private:
     enum rcprotocol_t _detected_protocol = NONE;
+    uint16_t _disabled_for_pulses;
     bool _detected_with_bytes;
     AP_RCProtocol_Backend *backend[NONE];
     bool _new_input = false;

libraries/AP_RCProtocol/AP_RCProtocol_PPMSum.h

@@ -18,8 +18,6 @@
 
 #include "AP_RCProtocol.h"
 
-#define MAX_PPM_CHANNELS 16
-
 class AP_RCProtocol_PPMSum : public AP_RCProtocol_Backend {
 public:
     AP_RCProtocol_PPMSum(AP_RCProtocol &_frontend) : AP_RCProtocol_Backend(_frontend) {}
@@ -30,4 +28,4 @@ private:
         int8_t _channel_counter;
         uint16_t _pulse_capt[MAX_RCIN_CHANNELS];
     } ppm_state;
-};
+};