SPC8106 S-MOS Systems, SPC8106 Datasheet - Page 145

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

bits 4-0
Miscellaneous Registers
bit 0
SPC8106
DE Auxiliary Enable Register RW
n/a
Setup Mode Video Enable Register
102h RW
n/a
Miscellaneous Output Register
3C2h W
VRTC
Polarity
This register exists in all SPC81xx series video controllers and should be used as DEh to guar-
antee software portability.
Only the 3 least significant bits of this address are decoded.
bit 1 of this register is a dummy read/write bit that has no effect in hardware. This read/write bit is
provided for compatibility of some software which expects to read valid setting of this VGA stan-
dard bit.
411-1.0
n/a
n/a
3CCh R
HRTC
Polarity
S-MOS Systems, Inc. • Tel: [phone] • Fax: [phone] • http://www.smos.com
Auxiliary Enable Code Bits [4:0]
The Auxiliary Enable Register can be used to prevent application software from accidentally over-
writing the Auxiliary Registers (3DF index 0-F). When disabled, the only Auxiliary Registers that
can be accessed are the Auxiliary Index Register (3DEh) and the Auxiliary Enable Register (3DFh
index 0Eh or 1Eh). The Auxiliary Registers are disabled by writing any value to the Auxiliary Enable
Register (index 0Eh or 1Eh), including the enable code 1Ah (the upper 3 bits of the enable byte are
ignored). The Auxiliary Registers are enabled for access after the enable code 1Ah is written to and
then read back from the Auxiliary Enable Register.
After a RESET, the Auxiliary Registers are disabled.
Video Subsystem Enable
Enables VGA for I/O and memory accesses.
n/a
n/a
Odd/Even
Page Bit
Auxiliary
Enable
Code Bit 4
n/a
n/a
X12-SP-001-07
Auxiliary
Enable
Code Bit 3
n/a
Clock Select
Bit 1
Auxiliary
Enable
Code Bit 2
n/a
Clock Select
Bit 0
Hardware Functional Specification
Auxiliary
Enable
Code Bit 1
n/a
Dummy En
DRAM
(see note)
Auxiliary
Enable
Code Bit 0
Video
Subsystem
Enable
3Dx/3Bx
Select
SP1-103