Connector - C64 User Port24 PIN MALE EDGE (DZM 12 DREH) at the computer.| Pin | Name | Description |
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| 1 | GND | Ground | | 2 | +5V | +5 VDC (100 mA max) | | 3 | /RESET | Reset, will force a Cold Start. Also a reset output for devices. | | 4 | CNT1 | Counter 1, from CIA #1 | | 5 | SP1 | Serial Port 1, from CIA #1 | | 6 | CNT2 | Counter 2, from CIA #2 | | 7 | SP2 | Serial Port 2, from CIA #2 | | 8 | /PC2 | Handshaking line, from CIA #2 | | 9 | ATN | Serial Attention In | | 10 | +9V AC | +9 VAC (+ phase) (100 mA max) | | 11 | +9V AC | +9 VAC (- phase) (100 mA max) | | 12 | GND | Ground | | | | | | A | GND | Ground | | B | /FLAG2 | Flag 2 | | C | PB0 | Data 0 | | D | PB1 | Data 1 | | E | PB2 | Data 2 | | F | PB3 | Data 3 | | H | PB4 | Data 4 | | J | PB5 | Data 5 | | K | PB6 | Data 6 | | L | PB7 | Data 7 | | M | PA2 | PA2 | | N | GND | Ground |
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