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Acorn Universal Interface Board (front)
Acorn Universal Interface Board (back)
This Acorn Universal Interface Board only has the 6522 fitted. The part number is 200,009 Issue 2.
This board connects to the standard Acorn bus and provides interfaces via the 3 integrated circuits listed below.
6522 - Versatile Interface Adapter
This device has 2 i/o ports which are each 10 bit parallel, TTL level (i.e. 8 individually proogrammable data bits plus 2 control bits) and a pair of interval timers for providing real time interrupts. One port connects to side B of the bus connector, the other via a high current buffer to the front of the board, wher a 26-way connector may be fitted. This connector is pin compatible with Centronics, Anadex and other printers.
INS8255 I/O port
The INS8255 is fitted in IC4 (not fitted) next to the bus connector and provides three 8-bit ports, two of which can be programmed to be all output ot all input and one can have direction programmed in 2 groups of 4 bits.
MC6850 Universal Asynchronous Receiver /Transmitted - (UART)
The MC 6850 is fitted in IC 5 (not fitted) next to the 6522 and provides serial interfacing together with an MC14411 bit rate generator IC which is fitted in IC6 next to the MC6850 (not fitted) and a 1.8432MHz crystal which enables standard baud rates in the range 75 to 9600 baud to be selected. Edge connectors on the front of the board provide a 20mA teletype connection and a RS232C connection. The 20mA serial input is via an optical isolator giving ground isolation between interconnected Acorn systems. The RS232C interface requires a +/- 12v supply which may be either connected via the front edge connector or can be provided by an optional on board 5v to +/- 12v converter module.
Here is the Acorn Universal Interface brochure.