Negate
PC
Reset (R)
A
read access to this register negates the
PC
reset line and allows the
(IFFFS
/
7FFF5)
PC
to start the boot procedure.
On
power-on the
PC
reset line
is
as-
serted (default).
Mode Register
(W)
Reading
this
register returns system configuration information
Bit
no. Name Function
0
SERON
serial interface enabled
1 PARON
parallel interface enabled
2
KEYON
keyboard interface enabled
3
MON
monochrome display emulation enabled
4
COLOR
color display emulation enabled
5
SEL1
select the
PCIAT
memory bank, s.b.
6
SE12
select the
PCIAT
memory bank, s.b.
7
PCIAT
LOW
=
AT
mode
HlGH
=
PC
mode
Writing to this register sets system configuration information
Bit
no. Name Function
0
SERON
1
PARON
2
KEYON
3
MON
4
COLOR
5
SEL1
6
SE12
7
ISTOPCLK
switch serial interface on
switch parallel interface on
switch keyboard interface on
enable monochrome display emulation
enable
color display emulation
PCIAT
memory bank select, s.b.
PCIAT
memory bank select, s.b.
LOW
=
disable the clock for video
retrace and keyboard
HlGH
=
enable the clock for video
retrace and keyboard
SELZ
SE11
PC
memory
AT
memory
0
0
not used not used
0
1
AOOOO
-
AFFFF
HEX
AOOOO
-
AFFFF
HEX
1
0
DO000
-
DFFFF
HEX
D4000
-
DFFFF
H!3
1
1
EOOOO
-
EFFFF
HEX not used
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