SPC8106 S-MOS Systems, SPC8106 Datasheet - Page 160

• Manufacturer Part Number: SPC8106
• Description: LCD/CRT VGA CONTROLLER
• Manufacturer: S-MOS Systems

bits 7-0
bits 5-0
Hardware Functional Specification
SP1-118
LCD Lookup Table Write Address Register
3C8h RW
Lookup
Table Write
Addr Bit 7
LCD Lookup Table Data Register
3C9h RW
n/a
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Lookup
Table Write
Addr Bit 6
(see below)
n/a
Once a valid read address is set in this register, the lookup table or sprite palette entry can be read
by three successive reads (red, green, blue) of the Lookup Table Data Register 3C9h. After a suc-
cessful read operation (i.e. three successive reads), the read address is automatically incre-
mented.
Directly after writing an index value to this register, the RAMDAC/Lookup Table Status Register
Read/Write Mode Status bits 1-0 are both set to 1.
When AUX[0B] bit 7 = 1 writes to the read address are NOT disabled.
LCD Lookup Table Write Address Bits [7:0]
These 8 bits are used to select 1 of 256 lookup table registers to be written, when AUX[0B] bit 3 =
0.
When AUX[0B] bit 3 = 1, then this write address is used to select 1 of 4 internal sprite palette regis-
ters. In this case, only write addresses 0Ch - 0Fh select a valid hardware cursor/sprite palette loca-
tion. (In the current implementation, only the low 2 bits of the write address are actually decoded to
select 1 of 4 internal sprite palette registers. However, the specific addresses 0Ch-0Fh should be
used to maintain compatibility with the overlay registers used in the external RAMDAC.)
Once a valid write address is set in this register, the lookup table or sprite palette entry can be writ-
ten by three successive writes (red, green, blue) to the Lookup Table Data Register 3C9h. After a
successful write operation (i.e. three successive writes), the write address is automatically incre-
mented.
Directly after writing an index value to this register, the RAMDAC/Lookup Table Status Register
Read/Write Mode Status bits 1-0 are both set to 0.
When AUX[0B] bit 7 = 1 writes to this register are disabled.
LCD Lookup Table Data Bits [5:0]
The use of the LCD Lookup Table Data Register varies depending on the setting of AUX[02] bit 6
and on the setting of the Green-only/NTSC Weighting Select bit (Auxiliary Register index 01, bit 4).
The chip allows a color lookup or 2 different gray scale weighting schemes, applied to data as it is
written to the lookup table.
AUX[02] bit 6
1
Lookup
Table Write
Addr Bit 5
LCD
Lookup
Table Data
Bit 5
Aux [01] bit 4
Table 0-60 LCD Lookup Table Function Selection
Lookup
Table Write
Addr Bit 4
LCD
Lookup
Table Data
Bit 4
X
X12-SP-001-07
GS Weighting Function Selected
Color LCD mode - bypass GS weighting circuit
and enable 256x12 LUT
Lookup
Table Write
Addr Bit 3
LCD
Lookup
Table Data
Bit 3
Lookup
Table Write
Addr Bit 2
LCD
Lookup
Table Data
Bit 2
Lookup
Table Write
Addr Bit 1
LCD
Lookup
Table Data
Bit 1
Lookup
Table Write
Addr Bit 0
LCD
Lookup
Table Data
Bit 0
411-1.0
SPC8106