diff --git a/ueforth/arduino/arduino.fs b/ueforth/arduino/arduino.fs
index 7141ac5..32e9dd8 100644
--- a/ueforth/arduino/arduino.fs
+++ b/ueforth/arduino/arduino.fs
@@ -9,7 +9,7 @@
 ' arduino-key is key
 
 ( Map Arduino / ESP32 things to shorter names. )
-: pin ( n n -- ) swap digitalWrite ;
+: pin ( n pin# -- ) swap digitalWrite ;
 : adc ( n -- n ) analogRead ;
 : duty ( n n -- ) 255 min 8191 255 */ ledcWrite ;
 : freq ( n n -- ) 1000 * 13 ledcSetup drop ;
diff --git a/ueforth/site/index.html b/ueforth/site/index.html
index b1a89ab..55be485 100644
--- a/ueforth/site/index.html
+++ b/ueforth/site/index.html
@@ -203,6 +203,12 @@ ledcWriteTone ( channel freq )   Write tone frequency (x 1000)
 ledcWriteNote ( channel note octave -- freq )
 </pre>
 
+<h5>Short GPIO Names</h5>
+<pre>
+pin ( value pin# -- )   Set GPIO pin value
+adc ( pin# -- n )   Analog read pin, result 0-1023
+</pre>
+
 <h5>System</h5>
 <pre>
 MS ( n -- )