Heathkit H9 - Parallel Handshake Timing; Serial I;O Connections

Pase22
@
oDD/EVEN
PARITY
(E)
This input
(E)
to
the UART
selects
the type
of
parity
that
is
checked
by the
receiver and
generated
by the
transmitter
if
parity
was selected
as explained
above.
A logic
o
on
the
E input
(pin
36) will insert odd
parity
immediately after
the data
bits.
A logic
1
on
this
input
inserts even
parity immediately
after the data
bits.
Since
the
Terminal does
not use the
parity
bit, the
E
input
is not connected.
If
your
special
application
requires a
parity bit,
Pictorial
2-77
shows
how to
select
odd or
even
parity,
KEYBOARD
PROGRAMMING
A
jumper
wire connection
on the bottom
of
the
keyboard circuit
board
lets
you
select one of
four
repeat
rates; 3.7-,
7.5-,
\5-, or
30-characters
per
sec-
ond.
This is the
rate at which characters
are written on
the
screen when
the REPT
(repeat)
key and a character
key are
held down at the same time.
Refer to the
"Repeat
Rate"
instructions in the
"Readjustment"
section of
this Manual
if
you
want to change
the
repeat rate.
TYPICAL
TERMINAL/COMPUTER
SYSTEMS
Parallel
Input/Output
Connections
The
following
parallel I/O connector
chart
describes
the signal
on
each
pin
ofthe
parallel
I/O connector
on
the
rear
panel.
Odd/Even Parity
EVENPARITY
ODD
PAR Y
t/0 ctRcutl
BOARD
(ffiJ
oNlo o
o
N2o
o
oP o
o
++
ao
o
Nl
o o
o
N2o
o
oP
o
o
++
PICTORIAL
2.I7
PIN
#
DATA DESCRIPTION
7
2
3
4
5
6
7
8
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
BiI
T
Bit 8
Parallel
Output
o
Positive true logic.
o
High
Level Output Voltage
(Vo")
:
2.7 min.
@
-400
pA
(High
Level
Output Current).
o
LowLevel
OutputVoltage
(Y
ot\
:
0.4 Vmax.
@
amA
(Low
Level
Output Current).
o
Standard 74L5175
latches.
I
DAVo
Take Data o
Output
Data
Available
- Normally
high.
The
Video
Terminal
will hold
this line
low to
indicate
that there
is
data
available
at
the
parallel
output
for the external
device.
r
HighLevel
OutputVoltage[Vr")
:
2.7Y min.
@
-400
p.A
(High
Level Output
CurrentJ.
.
Low
Level Output
Voltage
[Vor)
:
0.4
V max.
@
a mA
(Low
Level Output
Current).
.
Refer to the
"Handshake
Timing"
section.
10