SPC8104 S-MOS Systems, SPC8104 Datasheet - Page 99

• Manufacturer Part Number: SPC8104
• Description: VGA LCD CONTROLLER
• Manufacturer: S-MOS Systems

SPC8104
13 Offset Register RW
bit 7
14 Underline Location Register RW
n/a
15 Dummy Vertical Blanking Start Register RW (see note below)
bit 7
16 Dummy Vertical Blanking End Register RW (see note below)
bit 7
17 Mode Control Register RW
RO Status
Read as 1
18 Line Compare Register RW
bit 7
24 Attribute Controller Addr/Data FF Register RO
Attribute Ctl
Index/Data
Registers and bits marked as “Dummy” are read/write bits that have no effect in hardware.
These registers and bits are provided for compatibility with some software that expects to use
the values stored in these bits. The Dummy R/W bits are:
index 00, 01, 02, 03, 04, 05, 06, 10, 15, 16 - all bits
index 07 - bits 7, 6, 5, 3, 2, 0
index 09, 0B, 14 - bits 6, 5
index 11 - bits 6, 3, 2, 1, 0
index 17 - bits 3, 2
Index 11 bit 7 Protect CRTC Registers 0-7 - when set to 1, this bit protects the following registers
and bits from being written: index 00, 01, 02, 03, 04, 05, 06 - all bits, and index 07 bits
7,6,5,3,2,1,0.
412-1.0
bit 6
Dummy
Double
Word Select
(see note)
bit 6
bit 6
Word/Byte
Mode Select
bit 6
n/a
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bit 5
Dummy
Count by 4
(see note)
bit 5
bit 5
MA0 Select
MA13/15
bit 5
n/a
bit 4
bit 4
bit 4
bit 4
n/a
bit 4
n/a
Dummy Vertical Blank Start
Dummy Vertical Blank End
Line Compare
X15-SP-001-08.1
Offset
bit 3
bit 3
bit 3
bit 3
Dummy
Count by 2
(see note)
bit 3
n/a
Underline Row Scan
Dummy
HRTC/2
(see note)
n/a
bit 2
bit 2
bit 2
bit 2
bit 2
Hardware Functional Specification
bit 1
bit 1
bit 1
bit 1
MA14
Select
MA14/rsc
bit 1
n/a
bit 0
bit 0
bit 0
bit 0
Compat
Mode Select
bit 0
n/a
SP1-73