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Česká verze

UR4 - an interface for ZX Spectrum

An interface which is based on peripheral circuit 8255. In addition there is a RESET button and one Kempston joystick slot. Logic input and output pins are available on a connector FRB 30. Registers of 8255 are mapped as described in following table.

Registr Decimal address
A 31
B 63
C 95
CWR 127

UR4 front UR4 behind
Schematic of UR4 interface - 37kB
Schematic of UR4 interface - 37kB

All the best and good luck from Petr Simandl
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Last change : 29.6.1999