removed bug notice since the issue resolved itself

external_control/external_control.ino

@@ -108,6 +108,7 @@ void runCommand(){
   String mode;
   uint8_t pin;
   String state;
+  uint8_t pwmState;
   switch ((char)command) {
     case 'R': // run setup() again
       Serial.print("R");
@@ -194,35 +195,67 @@ void runCommand(){
       Serial.print(analogRead(analogInputToDigitalPin(analogPin)));
       Serial.print("s");
       return;
-      case 'r': // read digital value
-        /*bug:
-         The following "r" (or any other text you may put there) will never get printed despite this code branch being executed. Don’t ask me why or how.
-         Tested on Linux Mint 20.1, Arduino IDE version 2:1.0.5+dfsg2-4.1
-         Tested with Arduino Uno and Nano 328P
-        */
-        Serial.print("r");
-        pin = waitForSerialInput(2).toInt();
-        if (pin >= NUM_DIGITAL_PINS) Serial.print("e");
-        else {
-          Serial.print(digitalRead(pin));
-          Serial.print("s");
-        }
-        return;
-      case 'w': // write digital pin
-        Serial.print("w");
-        pin = waitForSerialInput(2).toInt();
-        state = waitForSerialInput(1);
-        if (pin >= NUM_DIGITAL_PINS) Serial.print("e");
-        else if (state == "h") {
-          digitalWrite(pin, HIGH);
-          Serial.print("s");
-        } else if (state == "l") {
-          digitalWrite(pin, LOW);
-          Serial.print("s");
-        } else {
-          Serial.print("e");
-        }
-        return;
+    case 'r': // read digital value
+      Serial.print("r");
+      pin = waitForSerialInput(2).toInt();
+      if (pin >= NUM_DIGITAL_PINS) Serial.print("e");
+      else {
+        Serial.print(digitalRead(pin));
+        Serial.print("s");
+      }
+      return;
+    case 'w': // write digital pin
+      Serial.print("w");
+      pin = waitForSerialInput(2).toInt();
+      state = waitForSerialInput(1);
+      if (pin >= NUM_DIGITAL_PINS) Serial.print("e");
+      else if (state == "h") {
+        digitalWrite(pin, HIGH);
+        Serial.print("s");
+      } else if (state == "l") {
+        digitalWrite(pin, LOW);
+        Serial.print("s");
+      } else {
+        Serial.print("e");
+      }
+      return;
+    case 'p': // set a pwm pin
+      Serial.print("p");
+      pin = waitForSerialInput(2).toInt();
+      pwmState = waitForSerialInput(3).toInt();
+      if (digitalPinHasPWM(pin)) {
+        analogWrite(pin, pwmState);
+        Serial.print("s");
+      } else {
+        Serial.print("e");
+      }
+      return;
+    case 't': // toggle a pin
+      Serial.print("t");
+      if (toggleState(waitForSerialInput(2).toInt())==UNKNOWN_PIN) Serial.print("e");
+      else Serial.print("s");
+      return;
+    case 'l':
+      Serial.print("l");
+      state = waitForSerialInput(1);
+      if (state=="h") {
+        digitalWrite(LED_BUILTIN, HIGH);
+        Serial.print("s");
+      } else if (state=="l") {
+        digitalWrite(LED_BUILTIN, LOW);
+        Serial.print("s");
+      } else if (state=="t") {
+        toggleState(LED_BUILTIN);
+        Serial.print("s");
+      } else {
+        Serial.print("e");
+      }
+      return;
+    case 'q':
+      Serial.print("qs");
+      while (true) {
+      }
+      return;
     default:
       Serial.print("e");
   }
@@ -247,7 +280,6 @@ void setup(){
     Serial.read();
   }
   Serial.print("s\r\n");
-  // testing
 }
 
 void loop(){