improved comments

serialservo/serialservo.ino

@@ -4,7 +4,7 @@
 // serial servo PWM
 //
 // Neil Gershenfeld 7/28/21
-// Quentin Bolsee 7/12/2021 : add button
+// Quentin Bolsee 12/7/21 : add button
 //
 // This work may be reproduced, modified, distributed,
 // performed, and displayed for any purpose, but must
@@ -34,6 +34,7 @@ void loop() {
    if (SerialUSB.available()) {
       SerialUSB.readBytes((char *)&duration,2);
       if (duration == 65535L) {
+         // special command, reply with button value
          int btn = digitalRead(BUTTON);
          SerialUSB.write(btn ? '1' : '0');
          }

serialstep/serialstep.ino

@@ -4,7 +4,7 @@
 // serial step-and-direction
 //
 // Neil Gershenfeld 4/11/21
-// Quentin Bolsee 7/12/2021 : add button
+// Quentin Bolsee 12/7/21 : add button
 //
 // This work may be reproduced, modified, distributed,
 // performed, and displayed for any purpose, but must
@@ -82,6 +82,7 @@ void loop() {
          digitalWrite(STEP,LOW);
          }
       else if (c == '?') {
+         // reply with button value
          int btn = digitalRead(BUTTON);
          SerialUSB.write(btn ? '1' : '0');
          }