MEC1404 Datasheet, PDF (398/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
Offset ^0Ch
Bits
Description
7:4 UPDATE_STEP1
Amount the current duty cycle is adjusted at the end of every PWM
period when the segment index is equal to 001.
3:0 UPDATE_STEP0
Amount the current duty cycle is adjusted at the end of every PWM
period when the segment index is equal to 000.
Type
R/W
R/W
Default
0h
Reset
Event
nSYSR
ST
0h
nSYSR
ST
28.10.5 LED UPDATE INTERVAL REGISTER
This register has eight segment fields which provide the number of PWM periods between updates to current duty cycle.
Segment field selection is decoded based on the segment index. The segment index equation utilized depends on the
SYMMETRY bit in the LED Configuration Register Register)
• In Symmetric Mode the Segment_Index[2:0] = Duty Cycle Bits[7:5]
• In Asymmetric Mode the Segment_Index[2:0] is the bit concatenation of following: Segment_Index[2] = (FALLING
RAMP TIME in Figure 28-3, "Clipping Example") and Segment_Index[1:0] = Duty Cycle Bits[7:6].
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 if the Enable Update bit in the LED Configuration register is
set to 1. Reads of this register return the current contents and not the value of the holding register.
Offset ^10h
Bits
Description
31:28 UPDATE_INTERVAL7
The number of PWM periods between updates to current duty cycle
when the segment index is equal to 111b.
15=Wait 16 PWM periods
…
0=Wait 1 PWM period
27:24 UPDATE_INTERVAL6
The number of PWM periods between updates to current duty cycle
when the segment index is equal to 110b.
15=Wait 16 PWM periods
…
0=Wait 1 PWM period
23:20 UPDATE_INTERVAL5
The number of PWM periods between updates to current duty cycle
when the segment index is equal to 101b.
15=Wait 16 PWM periods
…
0=Wait 1 PWM period
19:16 UPDATE_INTERVAL4
The number of PWM periods between updates to current duty cycle
when the segment index is equal to 100b.
15=Wait 16 PWM periods
…
0=Wait 1 PWM period
Type
R/W
R/W
R/W
R/W
Default
0h
Reset
Event
nSYSR
ST
0h
nSYSR
ST
0h
nSYSR
ST
0h
nSYSR
ST
DS00001956D-page 398
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