AP_RCProtocol: added multi-channel read() API

and use pulse_input_enable() to disable pulse input when not needed

libraries/AP_RCProtocol/AP_RCProtocol.cpp

@@ -25,6 +25,8 @@
 #include "AP_RCProtocol_ST24.h"
 #include <AP_Math/AP_Math.h>
 
+extern const AP_HAL::HAL& hal;
+
 void AP_RCProtocol::init()
 {
     backend[AP_RCProtocol::PPM] = new AP_RCProtocol_PPMSum(*this);
@@ -148,6 +150,9 @@ void AP_RCProtocol::process_byte(uint8_t byte, uint32_t baudrate)
                 memset(_good_frames, 0, sizeof(_good_frames));
                 _last_input_ms = now;
                 _detected_with_bytes = true;
+
+                // stop decoding pulses to save CPU
+                hal.rcin->pulse_input_enable(false);
                 break;
             }
         }
@@ -240,6 +245,13 @@ uint16_t AP_RCProtocol::read(uint8_t chan)
     return 0;
 }
 
+void AP_RCProtocol::read(uint16_t *pwm, uint8_t n)
+{
+    if (_detected_protocol != AP_RCProtocol::NONE) {
+        backend[_detected_protocol]->read(pwm, n);
+    }
+}
+
 /*
   ask for bind start on supported receivers (eg spektrum satellite)
  */

libraries/AP_RCProtocol/AP_RCProtocol.h

@@ -64,6 +64,7 @@ public:
     }
     uint8_t num_channels();
     uint16_t read(uint8_t chan);
+    void read(uint16_t *pwm, uint8_t n);
     bool new_input();
     void start_bind(void);
 

libraries/AP_RCProtocol/AP_RCProtocol_Backend.cpp

@@ -46,6 +46,14 @@ uint16_t AP_RCProtocol_Backend::read(uint8_t chan)
     return _pwm_values[chan];
 }
 
+void AP_RCProtocol_Backend::read(uint16_t *pwm, uint8_t n)
+{
+    if (n >= MAX_RCIN_CHANNELS) {
+        n = MAX_RCIN_CHANNELS;
+    }
+    memcpy(pwm, _pwm_values, n*sizeof(pwm[0]));
+}
+
 /*
   provide input from a backend
  */

libraries/AP_RCProtocol/AP_RCProtocol_Backend.h

@@ -28,6 +28,7 @@ public:
     virtual void process_pulse(uint32_t width_s0, uint32_t width_s1) {}
     virtual void process_byte(uint8_t byte, uint32_t baudrate) {}
     uint16_t read(uint8_t chan);
+    void read(uint16_t *pwm, uint8_t n);
     bool new_input();
     uint8_t num_channels();