A standard NASBUS 8″ x 8″ PCB: twelve may
be fitted to a system to use all 256 available ports, each board with
three parallel input/output controllers, one counter timer circuit and
one universal asynchronous receiver-transmitter. Each board may be fitted
only with the options necessary, though later uprates are simple. Boards
are supplied with documentation covering all options.
Each device carries two 8-bit read/write
parallel data ports with separate control signals; applications for this
type of device include direct interfacing with many digital-to-analogue
and analogue convertors, the control of relays or electronic power
controllers and uncomplicated EPROM programming.
The use of this device saves complex
programming when the system is required to count or time internal or
external events; essential for instrumentation, process control and
experimental robotics, it permits a higher program speed without
Supplied with its own crystal clock and
monolithic baud rate generator, this device frees the system computer’s
serial port to allow simultaneous operation of, for example, a cassette
mass storage system and a printer. A V24/RS232C serial interface is
also provided for direct connection to terminals and VDUs.