AMD Geode LX 800@0.9W - Manual (Page 314)

314 AMD Geode™ LX Processors Data Book
Display Controller Register Descriptions 33234H
6.6.3.2 DC General Configuration (DC_GENERAL_CFG)
This register contains general control bits for the DC. Unless otherwise noted in the bit descriptions table, settings written to
this register do not take effect until the start of the following frame or interlaced field.
DC Memory Offset 004h
Type
R/W
Reset Value 00000000h
DC_GENERAL_CFG Register Map
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
DB
U
G
DBSL CF
R
W
DIA
G
CRC
_MOD
E
SGFR SGRE SIG
E
SIG_SEL FRC
8
PIX
RSVD YUVM VDSE VG
A
F
T
FD
T
Y
STFM
DFHPEL DFHPSL
VG
A
E
DECE CMPE
FIL
T
_SIG_SEL VI
D
E
C
L
R_CU
R
C
URE
DFL
E
DC_GENERAL_CFG Bit Descriptions
Bit Name Description
31 DBUG Debug Mode. Effective immediately.
0: Disable
1: Enable.
30 DBSL Debug Select. Effective immediately.
0: FIFO control signals transmitted to debug port.
1: Memory control signals transmitted to debug port.
29 CFRW Compressed Line Buffer Read/Write Select. Effective immediately.
Only has effect if in DIAG mode (bit 28 = 1).
0: Write address enabled to Compressed Line Buffer (CLB) in diagnostic mode.
1: Read address enabled to CLB in diagnostic mode.
28 DIAG RAM Diagnostic Mode. Effective immediately.
0: Normal operation.
1: RAM diagnostic mode. This bit allows testability of the on-chip Display FIFO and CLB
via the diagnostic access registers. A low to high transition resets the Display FIFO
and Compressed Line Buffer read and write pointers.
27 CRC_MODE CRC Mode. Effective immediately.
This bit selects the CRC algorithm used to compute the signature.
0: nxt_crc[23:0] <= {crc[22:0], (crc[23], crc[3], crc[2])} ^ data[23:0].
1: nxt_crc = (reset) ? 32’h01 :( {crc[30:0], 1’b0} ^ ((crc[31]) ? 32’h04c11db7 : 0) )^ data.
26 SGFR Signature Free Run. Effective immediately.
0: Capture display signature for one frame.
1: Capture display signature continuously for multiple frames.
When this bit is cleared, the signature accumulation stops at the end of the current frame.
25 SGRE Signature Read Enable. Effective immediately.
0: Reads to DC_PAL_DATA (DC Memory Offset 074h[23:0]) return palette data.
1: Reads to DC_PAL_DATA (DC Memory Offset 074h[23:0]) return signature data. The
palette address register contents are ignored in this case. Note that the automatic pal-
ette address increment mechanism will still operate even though the address is
ignored.