APPENDIX
9.8
VER.V09F
SECTION 9.8
PORT ALLOCATIONS
HUNTER uses the NSC800 port map for all its I/O functions,
including the keyboard, RS-232, etc. The following gives a list
of the most useful ports which can be controlled from Basic
using OUT or INP verbs or from machine code.
Address
Decimal Hex
2
96
129
130
131
132
133
1H
2H
60H
81H
82H
83H
84H
85H
Name
DSR
INPUTS
ANGLE
V240UT
RTS
POWHLD
INVCON
DTR
Description
Bit seven is the DSR input
bit.
1
= Inactive
2
= Active
This port has a number of
input functions:
Bit O
= Data in (inverted
from RS-232 line)
Bit 1
= DCD -
11
-
Bit 2 = Power low warning
1 = Power O.K
0
= Power low
Bit 3
= TXCLK -
11
-
also the
single input bit.
Controls display viewing
angle. Input value in the
range 0-1FH
Directly outputs
data line signal
The output is
inverted i.e.
0
= +Ve 1 = -VE
RTS output bit
Power control
to the V24
on bit 0.
voltage
bit O
= 1 HUNTER on
bit O
= 0: HUNTER off
V24 inverter control
bit O
= 1 : inverter on
bit O
= 0: inverter off
DTR output bit
PAGE 9 - 39
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