LEDs module
===========

The LEDs module allows controlling the LEDs of the board.


Python API example
------------------

.. code-block:: python

    # Adjust LEDs brightness
    # 0 is minimum
    # 1 is maximum
    scaffold.leds.brightness = 0.5

    # Toggle a LED every second
    scaffold.leds.d0.mode = LEDMode.VALUE
    for i in range(10):
        time.sleep(1)
        scaffold.d0 << 1
        time.sleep(1)
        scaffold.d0 << 0

    # Now flash the LED every second
    scaffold.leds.d0.mode = LEDMode.EVENT
    for i in range(10):
        time.sleep(1)
        scaffold.d0 << 1
        time.sleep(1)
        scaffold.d0 << 0


LEDs mode
---------

A/B/C/D LEDs can be lit according to two different modes:

- Event mode: the LED will flash when an rising or falling edge occurs on the
  monitored signal. This is the default mode. This mode allows seeing activity
  on the LED even when very short pulses happen.
- Value mode: the LED is ON when the monitored signal is high. When using this
  mode, a user may not be able to catch very short pulses. This mode is more
  appropriate for watching slow signals.


Registers
---------

+--------+------------+---+
| 0x0200 | control    | W |
+--------+------------+---+
| 0x0201 | brightness | W |
+--------+------------+---+
| 0x0202 | leds_0     | W |
+--------+------------+---+
| 0x0203 | leds_1     | W |
+--------+------------+---+
| 0x0204 | leds_2     | W |
+--------+------------+---+
| 0x0205 | mode       | W |
+--------+------------+---+


control register
^^^^^^^^^^^^^^^^

+---+---+---+---+---+---+----------+---------+
| 7 | 6 | 5 | 4 | 3 | 2 | 1        | 0       |
+---+---+---+---+---+---+----------+---------+
| *reserved*            | override | disable |
+-----------------------+----------+---------+

disable
  Write 1 to disable TLC5927 drivers output. Default is 0 (enabled).
override
  Sets the LEDs of the board to the values defined in led_n registers.


brightness registers
^^^^^^^^^^^^^^^^^^^^

+------------+---+---+---+---+---+---+---+
| 7          | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+------------+---+---+---+---+---+---+---+
| *reserved* | brightness                |
+------------+---------------------------+

brightness
  7-bits word which controls the brightness of the LEDs. See TLC5952 datasheet
  for more details.


leds_n registers
^^^^^^^^^^^^^^^^

*leds_n* registers define the state of the LEDs of the board when override bit
is set. Set a bit to 1 to turn the corresponding LED on, 0 to turn it off. Value
on reset is 0x00.


mode register
^^^^^^^^^^^^^

+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+---+---+---+---+---+---+
| 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9  | 8  | 7  | 6  | 5 | 4 | 3 | 2 | 1 | 0 |
+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+----+---+---+---+---+---+---+
| *reserved*                  | d5 | d4 | d3 | d2 | d1 | d0 | c1 | c0 | b1 | b0 | a1 | a0 | *reserved*            |
+-----------------------------+----+----+----+----+----+----+----+----+----+----+----+----+-----------------------+

mode register is a 24-bit register. Write three times to update all the bits of
this register.

Each bit of this register sets the lighting mode of a LED. When bit is 0, the
corresponding LED will blink on a falling or rising edge of the monitored
signal. When the bit is 1, the LED will be lit as long as the monitored
signal is high. Default mode is 0 (event mode) for all LEDs.