docs/esp32: Fix machine.Timer quickref to specify HW timers.
Also remove trailing spaces on other lines.
@@ -118,17 +118,21 @@ Use the :mod:`time <utime>` module::
Timers
------
-Virtual (RTOS-based) timers are supported. Use the :ref:`machine.Timer <machine.Timer>` class
-with timer ID of -1::
+The ESP32 port has four hardware timers. Use the :ref:`machine.Timer <machine.Timer>` class
+with a timer ID from 0 to 3 (inclusive)::
from machine import Timer
- tim = Timer(-1)
- tim.init(period=5000, mode=Timer.ONE_SHOT, callback=lambda t:print(1))
- tim.init(period=2000, mode=Timer.PERIODIC, callback=lambda t:print(2))
+ tim0 = Timer(0)
+ tim0.init(period=5000, mode=Timer.ONE_SHOT, callback=lambda t:print(0))
+
+ tim1 = Timer(1)
+ tim1.init(period=2000, mode=Timer.PERIODIC, callback=lambda t:print(1))
The period is in milliseconds.
+Virtual timers are not currently supported on this port.
+
.. _Pins_and_GPIO:
Pins and GPIO
