Lsi (Hd43110) - Radio Shack TRS-80 26-3650 Service Manual

3.
LSI
(HD43110)
HD431 10
is
a cassette
tape
interface
LSI
with Kansas
City standards
which
transfers
data
between
the
CPU
and
cassette
tape
recorder.
Data
"0" and "1"
are transferred
in serial
as
1,170
Hz
and 2,340
Hz
frequency pulse respectively.
Data
is
transferred at
300
bits
per second.
The
following
lists
the functions of each terminal of the LSI.
Pin No. Signal
Name
In/Out
Function
2
OSC
In
Clock
pulse
(32,768Hz)
input.
7
VDD' Out
-3V
output.
8
CONT
In
The
LSI functions
only
when
the terminal
is
HIGH.
9
VDD1
In
-3V
input.
10
CE
In
Chip
enable terminal.
The
LSI
is
designated
from
PC- 4
when
the terminal
is
HIGH.
11
SP
In
Strobe pulse input
from
PC-4.
13
D4
In/Out
Serial
data input/output.
14
GND
In
0V
input terminal.
17
C3
In
Data input
from
cassette tape.
18
C2
Out Data output to cassette tape.
19
C1
Out
Remote
control (auto stop)
signal
output.
-
17
-