User's Manual

3. Specification
3.1 The Z80 second processor
A second processor for the BBC Microcomputer model B, operating
through the Tube, providing the ability to run sophisticated software
under the CP/M 2.2 operating system.
The second processor is housed in a rigid injection moulded
thermoplastic case and contains the fo11owing:
A 6MHz Z80B CPU
64K of read/write Random Access Memory
4K Read Only Memory ("shadow ROM") providing a boot function on power-
up and to handle Non-Maskable Interrupts (NMI) from the Host processor
via the Tube.
The Tube - a fast asynchronous communication path connecting the
second processor to the I/O processor (BBC Microcomputer).
A mains-operated integral power supply comprising a mains transformer
and power supply board.
3.2 Power Supply
Max. AC Input 264V AC
MIN. AC Input 216V AC
Power Rating 14 watts
Supply Frequency 47-63Hz
Max. Output Current lA at +5V