MEC1404 Datasheet, PDF (395/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
Offset ^00h
Bits
Description
Type
6 ENABLE_UPDATE
This bit is set to 1 when written with a ‘1’. Writes of ‘0’ have no effect.
Hardware clears this bit to 0 when the breathing configuration regis-
ters are updated at the end of a PWM period. The current state of the
bit is readable any time.
R/WS
Default
0b
Reset
Event
nSYSR
ST
This bit is used to enable consistent configuration of LED_DELAY,
LED_STEP and LED_INT. As long as this bit is 0, data written to
those three registers is retained in a holding register. When this bit is
1, data in the holding register are copied to the operating registers at
the end of a PWM period. When the copy completes, hardware
clears this bit to 0.
5:4 PWM_SIZE
R/W
This bit controls the behavior of PWM:
0b
nSYSR
ST
3=Reserved
2=PWM is configured as a 6-bit PWM
1=PWM is configured as a 7-bit PWM
0=PWM is configured as an 8-bit PWM
3 SYNCHRONIZE
R/W
When this bit is ‘1’, all counters for all LEDs are reset to their initial
values. When this bit is ‘0’ in the LED Configuration Register for all
LEDs, then all counters for LEDs that are configured to blink or
breathe will increment or decrement, as required.
0b
nSYSR
ST
To synchronize blinking or breathing, the SYNCHRONIZE bit should
be set for at least one LED, the control registers for each LED should
be set to their required values, then the SYNCHRONIZE bits should
all be cleared. If the all LEDs are set for the same blink period, they
will all be synchronized.
2 CLOCK_SOURCE
R/W
This bit controls the base clock for the PWM. It is only valid when
CNTRL is set to blink (2).
0b
nSYSR
ST
1=Clock source is the 48 MHz clock
0=Clock source is the 32.768 KHz clock
1:0 CONTROL
R/W
This bit controls the behavior of PWM:
3=PWM is always on
2=LED blinking (standard PWM)
1=LED breathing configuration
0=PWM is always off. All internal registers and counters are reset to
0. Clocks are gated
00b
nSYSR
ST
11b
WDT TC
28.10.2 LED LIMITS REGISTER
This register may be written at any time. Values written into the register are held in an holding register, which is trans-
ferred into the actual register at the end of a PWM period. The two byte fields may be written independently. Reads of
this register return the current contents and not the value of the holding register.
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DS00001956D-page 395