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PORT PIN DESCRIPTION

PIN	DESCRIPTION	NOTES
TOP SIDE
1	GROUND
2	+5V	(100 mA MAX.)
3	RESET	By grounding this pin, the Commodore 64 will do a COLD START, resetting completely. The pointers to a BASIC program will be reset, but memory will not be cleared. This is also a RESET output for the external devices.
4	CNT1	Serial port counter from CIA#1(SEE CIA SPECS)
5	SP1	Serial port from CIA #l (SEE 6526 CIA SPECS)
6	CNT2	Serial port counter from CIA#2(SEE CIA SPECS)
7	SP2	Serial port from CIA #l (SEE 6526 CIA SPECS)
8	PC2	Handshaking line from CIA #2 (SEE CIA SPECS)
9	SERIAL ATN	This pin is connected to the ATN line of the serial bus.
10	9 VAC+phase	Connected directly to the Commodore 64 transformer (50 mA MAX.).
11	9 VAC-phase
12	GND
BOTTOM SIDE
A	GND	The Commodore 64 gives you control over PORT B on CIA chip #1. Eight lines for input or output are available, as well as 2 lines for handshaking with an outside device. The I/O lines for PORT B are controlled by two locations. One is the PORT itself, and is located at 56577 ($DD01 HEX). Naturally you PEEK it to read an INPUT, or POKE it to set an OUTPUT. Each of the eight I/O lines can be set up as either an INPUT or an OUTPUT by by setting the DATA DIRECTION REGISTER properly.
B	FLAG2
C	PB0
D	PB1
E	PB2
F	PB3
H	PB4
I	PB5
K	PB6
L	PB7
M	PA2
N	GND

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This page has been created by Sami Rautiainen.
Read the small print.	Last updated November 06, 1998.