Document tasks.

ueforth/site/ESP32forth.html

@@ -170,8 +170,9 @@ adc ( pin# -- n )   Analog read pin, result 0-1023
 
 <h5>System</h5>
 <pre>
-MS ( n -- )
-TERMINATE ( n -- ) Call system exit
+MS ( n -- ) Pause for some number of milliseconds.
+MS-TICKS ( -- n ) Time since start in milliseconds.
+TERMINATE ( n -- ) Call system exit.
 </pre>
 
 <h5>Files</h5>
@@ -356,8 +357,28 @@ esp_intr_free ( handle -- 0/err )
 timer_isr_register ( group timer xt arg ret -- 0/err )
 </pre>
 
+<h5 id="tasks">Tasks</h5>
+These words are inside the <code>TASKS</code> vocabulary.
+
+<pre>
+PAUSE ( -- ) Yield to other tasks.
+MS ( n -- ) Pause for some number of milliseconds (yields to other tasks).
+TASK ( xt dsz rsz "name" -- ) Create a new task with dsz size data stack
+                              and rsz size return stack running xt.
+START-TASK ( task -- ) Activate a task.
+.TASKS ( -- ) List running tasks.
+
+Example:
+tasks
+: hi   begin ." Time is: " ms-ticks . cr 1000 ms again ;
+' hi 100 100 task my-counter
+my-counter start-task 
+</pre>
+
 <h5 id="timers">Timers</h5>
 These words are inside the <code>TIMERS</code> vocabulary.
+<br/><b>NOTE: These are low level ESP32 timers. For a periodic background
+operation, you'll probably want to use <a href="#tasks">TASKS</a>.</b>
 
 <p>High Level words:</p>
 <pre>