AMD Geode LX 800@0.9W - Manual (Page 371)

AMD Geode™ LX Processors Data Book 371
Display Controller Register Descriptions 33234H
Table 6-55 illustrates the various frame buffer addressing schemes. In the table, MAx represents the frame buffer memory
address signals, Ax represents the CRTC address counter signals, RSx represents row scan counter output bits. The
binary value in the column headings is a concatenation of the DWORD Mode and Byte Mode bits. (i.e., {DWORD Mode,
ByteMode} in verilog.)
1 SL_RSCBT Select Row Scan Bit. This bit determines which CRTC signal appears on the MA14
address bit sent to the frame buffer memory. If this bit is a 0, bit 1 of the Row Scan
counter appears on MA14. If this bit is a 1, then CRTC address counter bit 14, 13, or 12
appears on MA14. See Table 6-55 on page 371 for more information.
0 SL_A13 Select A13. This bit determines which CRTC signal appears on the MA13 address bit
sent to the frame buffer memory. If this bit is a 0, bit 0 of the Row Scan counter appears
on MA13. If this bit is a 1, then CRTC address counter bit 13, 12, or 11 appears on MA13.
See Table 6-55 on page 371 for more information.
Table 6-55. CRTC Memory Addressing Modes
Frame Buffer Memory Address Bit Byte Mode (01) Word Mode (00) DWORD Mode (1X)
MA0 A0 A15 or A13 A12
MA1 A1 A0 A13
MA2 A2 A1 A0
MA3 A3 A2 A1
MA4 A4 A3 A2
MA5 A5 A4 A3
MA6 A6 A5 A4
MA7 A7 A6 A5
MA8 A8 A7 A6
MA9 A9 A8 A7
MA10 A10 A9 A8
MA11 A11 A10 A9
MA12 A12 A11 A10
MA13 A13 or RS0 A12 or RS0 A11 or RS0
MA14 A14 or RS1 A13 or RS1 A12 or RS1
MA15 A15 A14 A13
CRTC Mode Control Register Bit Descriptions (Continued)
Bit Name Description