AMD Geode™ LX Processors Data Book
291
Display Controller
33234H
6.5.5.4
Read Modes
There are two read modes provided to assist the CPU with
graphics operations in planar modes. Read mode 0 simply
returns the frame buffer data. Read mode 1 allows the CPU
to do a single color compare across eight pixels. Figure 6-
18 shows the data flow for read modes. Figure 6-19 on
page 292 shows how the color compare logic in Figure 6-
18 works.
Figure 6-18. Read Mode Data Flow
Memory Read Data [31:0]
Read Map Select [1:0]
Chain2
Chain4
CPU A[1:0]
Select Read
Map Logic
ReadMode1
B
CPU Read Data [7:0]
In [31:0]
Out [7:0]
Color Compare
In [31:0]
Out [7:0]
Color Compare [3:0]
Color Don’t Care [3:0]
A
B
Logic
Summary of Contents for Geode LX 600
Page 14: ...14 AMD Geode LX Processors Data Book Overview 33234H...
Page 20: ...20 AMD Geode LX Processors Data Book Architecture Overview 33234H...
Page 44: ...44 AMD Geode LX Processors Data Book Signal Definitions 33234H...
Page 88: ...88 AMD Geode LX Processors Data Book GLIU Register Descriptions 33234H...
Page 618: ...618 AMD Geode LX Processors Data Book Electrical Specifications 33234H...