AP_HAL: fixed and updated RCInput example.

libraries/AP_HAL/examples/RCInput/RCInput.cpp

@@ -8,7 +8,7 @@ const AP_HAL::HAL& hal = AP_HAL::get_HAL();
 
 #define MAX_CHANNELS 16
 
-static uint8_t max_channels = 0;
+static uint8_t max_channels_display = 8;  //Set to 0 for display numbers of channels detected.
 static uint16_t last_value[MAX_CHANNELS];
 
 void setup(void) 
@@ -16,28 +16,35 @@ void setup(void)
     hal.console->printf("Starting RCInput test\n");
 }
 
-void loop(void) 
+void loop(void)
 {
     bool changed = false;
-    uint8_t nchannels = hal.rcin->num_channels();
+    uint8_t nchannels = hal.rcin->num_channels(); //Get the numbers channels detected by RC_INPUT.
     if (nchannels > MAX_CHANNELS) {
         nchannels = MAX_CHANNELS;
     }
-    for (uint8_t i=0; i<nchannels; i++) {
-        uint16_t v = hal.rcin->read(i);
-        if (last_value[i] != v) {
-            changed = true;
-            last_value[i] = v;
+    if (nchannels != 0) {  //If channels detected, process.
+        for (uint8_t i = 0; i < nchannels; i++) {
+            uint16_t v = hal.rcin->read(i);
+            if (last_value[i] != v) {
+                changed = true;
+                last_value[i] = v;
+            }
         }
-        if (i > max_channels) {
-            max_channels = i;
+        if (max_channels_display > nchannels) {
+            max_channels_display = nchannels;
         }
-    }
-    if (changed) {
-        for (uint8_t i=0; i<max_channels; i++) {
-            hal.console->printf("%2u:%04u ", (unsigned)i+1, (unsigned)last_value[i]);
+        if (max_channels_display > 0) {
+            if (changed) {
+                for (uint8_t i = 0; i < max_channels_display; i++) {
+                    hal.console->printf("%2u:%04u ", (unsigned)i+1, (unsigned)last_value[i]);
+                }
+                hal.console->println();
+            }
+        } else {
+            hal.console->printf("Channels detected: %2u\n", nchannels);
+            hal.console->printf("Set max_channels_display > 0 to display channels values\n");
         }
-        hal.console->println();
     }
     hal.scheduler->delay(100);
 }