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Command
Binary
lines
Mode
Statement
Representation
POKE 59459,255
11111111
PA0·7
Output
POKE 59459,0
00000000
PA0-7
Input
POKE 59459,240
11110000
PA0-3
Input
PA4-7
Output
table 7.8. Parallel user port example.
Programming
01
lines PAO·7 for Inputfoutput operation.
SECOND CASSETTE INTERFACE (Connector J3)
This interface is brought out from the PET main logic board to a 6 position,
12
contact edge connector
with .156 inch spacing between contact centers (See Figure 7.9).
A keying slot is located between pins
2-3.
This port is intended for use with the Commodore second cassette system only. Any other connections
are made at the risk of the user. Please note that
+
5 volts is
not
intended for use as an external power
supply.
Table 7.10 shows the PET pin identification characters, labels and descriptions. Table 7.11 shows some
typical receptacles that are suitable for the second cassette connector.
FROM PET MAIN LOGIC ASSEMBLY BOARD
Top
View
. /
Upper
/ "
Contact
Insulation
6
. / (or Pin)
~12345
F
·~I :~:==:===:
===:
~:5
Lower
A B C
D
E
"' F "
Contact
{or Pin}
Rear or Edge-on View
th~ugh
slot in PET
Figure 7.9. Simplified view 01 edge connector J3
with contact Identlllcation.
Note A·1, B-2, etc.. imply a pin A to pin1, pin B to pin 2, connection.
In some special units, pins 1 through 6 were not connected.
Pin
Identification
Label
Description
Characters
A·,
GND
Digital ground.
B·2
+5
Positive 5 volts to operate cassette circuitry
only.
e·3
Motor
Computer controlled positive 6 volts for
cassette motor.
D-4
Read
Read line from cassette.
E-5
Write
Write line to cassette.
F-6
Sense
Monitors closure of mechanical switch on
cassette when any button is pressed.
Table 7.10. second cassette interface port.
PET pin Identification characters, labels and associated descriptions.
62
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