Brightness – Cirrus Logic EP93xx User Manual
Page 232
7-50
DS785UM1
Copyright 2007 Cirrus Logic
Raster Engine With Analog/LCD Integrated Timing and Interface
EP93xx User’s Guide
7
7
7
If the Offset value is 0x0, no offset is used and addressing
proceeds normally.
Other Video Registers
Brightness
Address: 0x8003_0020
Default: 0x0000_0000
Definition: Brightness Control register.
Bit Descriptions:
RSVD:
Reserved - Unknown during read
CMP:
Compare - Read/Write
The Compare value written to this field determines the
brightness control duty cycle (see CNT below) - that is,
when the brightness signal to the BRIGHT pin is ‘1’ or ‘0’.
CNT:
Count - Read/Write
The Count value written to this field specifies the number
of horizontal lines counted during a brightness waveform
period. The counter counts down from the Count value to
0x0.
The CNT value and the CMP value are used to construct a
brightness control waveform on the BRIGHT pin by this
relationship:
When Count > Compare, or Count = Compare, the
brightness signal to the BRIGHT pin is ‘0’.
When Count < Compare, the brightness signal to the
BRIGHT pin is ‘1’.
The BRIGHT pin is ‘0’ (zero% brightness) after reset.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RSVD
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CMP
CNT