User Port Extension Header

User Port Extension Header

Pin Name Description Special Purpose
1 GND Ground  
2 +5V +5 VDC (200 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  
10 12VDC 12VDC (Max 500mA)  
11 12VDC 12VDC (Max 500mA)  
12 GND Ground  
13 USRCTL0 FPGA Pin, NOT 5V tolerant! LED Clock
A GND Ground (RS232: GND)  
B /FLAG2 Flag 2 (RS232: RxD=Both B+C)  
C PB0 Data 0 (RS232: RxD=Both B+C)  
D PB1 Data 1 (RS232: RTS)  
E PB2 Data 2 (RS232: DTR)  
F PB3 Data 3 (RS232: RI)  
H PB4 Data 4 (RS232: DCD)  
J PB5 Data 5  
K PB6 Data 6 (RS232: CTS)  
L PB7 Data 7 (RS232: DSR)  
M PA2 PA2 (RS232: TxD)  
N GND Ground (RS232: GND)  
P USRCTL1 FPGA Pin, NOT 5V tolerant! LED Data

Applies to: Ultimate 64

Note that the row 1-12 corresponds to the upper row of the User Port card edge fingers on a C64, and that the row A-N corresponds to the bottom row of the User Port card edge fingers.

Pin 13 and P, the two left most pins on the header, are added for add features to the user port. One of the intended usages of these two pins is the generation of the “9 V~” on the user port extension board.

There is one other use of pin 13 and P, which is the control of a LED Strip. In this case, pin 13 the LED Clock and pin P is the LED Data, assuming a LED strip that is based on APA102C.

In the LED Strip configuration menu, the use of pind 13 and P can be chosen. When the LED Strip is set to ‘off’, the 9 V~ generation is enabled.

Attaching the User Port Adapter

The user port adapter accessory should be connected using a 26-pin ribbon cable. Note that there is only ONE correct way to connect it, and other ways may result in damage of the U64 itself or to the accessory.

Correct connection Ribbon Cable to the User Port Extension Header

Pay attention to the orientation!! The red wire should line up with pin 1!!!

Please make sure the connector is not shifted a whole row, or to the left or to the right:

Incorrect connection Ribbon Cable to the User Port Extension Header