Background – Cirrus Logic EP93xx User Manual
Page 299
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Copyright 2007 Cirrus Logic
Graphics Accelerator
EP93xx User’s Guide
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MASK:
Mask - Read/Write
For a Block Copy function, the value in this field specifies
the logical mask, if used. If BG = ‘1’, M = ‘00’, and REMAP
= ‘1’ in the
register, the value specifies the
destination foreground color for source image pixels = ‘1’.
For Block Fill and Line Draw functions, the value in this
field specifies the pixel color for the destination image.
The mask or color value is located in the least significant
BPP part of the register for modes less than 24 bpp. Bits
0-23 are used for 24 bpp mode, bits 0-15 are used for
16 bpp mode, bits 0-7 are used for 8 bpp mode, and bits
0-3 are used for 4 bpp mode.
BACKGROUND
Address:
0x8004_0030 - Read/Write
Default:
0x0000_0000
Mask:
0x00FF_FFFF
Definition:
Block Function Background Register
Bit Descriptions:
RSVD:
Reserved - Unknown during read
BG:
Background - Read/Write
When performing remap operations without transparency
(REMAP = ‘1’ and BG = ‘1’ in the
register),
the value in this field specifies the destination background
pixel color for source pixels that have a value of ‘0’.
Bits that are ‘1’ in this field can be used with Line Draw
functions to specify a ‘blank space’ in the drawn line.
The pixel color value is located in the least significant BPP
part of the field for modes less than 24 bpp.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RSVD
BG
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
BG