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Cumana 68008 2nd processor

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Cumana preproduction 68008 2nd processor

Cumana pre-production 68008 2nd processor (top)

This board is a Cumana 68008 Issue A second processor, which to me means it is a pre-production model. The battery at the bottom left has been removed because it was leaking.

The board contains:

2 x MC68C21P PIAs (Peripheral Interface Adapters) on the left side
HD146818P Real Time Clock beneath the MC68C21Ps
16MHz crystal beneath the HD146818P
An unknown IC marked RS "301-117" is to the right of the MC68C21P, I think this is a disc controller.
Floppy disc connector above the unknown IC
SASI connector above the FDD connector
The lower socket in the middle is connected to the BBC Micro via a ribbon cable which replaces the BBC Micro's 6502 CPU
The BBC Micro's 6502 CPU is plugged into the upper socket.
The MC68008P8 is the large IC in the top right
The 16 x HM50256P-15 ICs ( 256Kb DRAM) at the bottom right provide 512KB Dynamic RAM

Here is a Hires picture of the Cumana pre-production 68008 2nd processor

Cumana pre-production 68008 2nd processor bottom

Cumana pre-production 68008 2nd processor (bottom)

The bottom of the board shows a lot of wired patches which tend to confirm its status as pre-production.

Cumana 68008 "Mentor" 2nd processor (top)

This the Cumana 68008 "Mentor" Issue 1 second processor for the BBC Micro.

The board contains:

2 x MC68C21P PIAs (Peripheral Interface Adapters) on the left side
HD146818P Real Time Clock beneath the MC68C21Ps
16MHz crystal beneath the HD146818P
TMS2797NL floppy disc controller to the right of the MC68C21P
Floppy disc connector above the unknown IC
SASI connector above the FDD connector
The socket in the middle has a ROM labelled "BBC Boot DD 2/10/85". I think that this ROM goes in the BBC and the BBC Micro's 6502 goes in this socket.
The lower socket has been moved to the bottom of the board..
The MC68008P8 is the large IC in the top right
The 16 x HM50256P-15 ICs ( 256Kb DRAM) at the bottom right provide 512KB Dynamic RAM

Here is a HiRes picture of the Cumana 68008 "Mentor" 2nd processor .

Cumana 68008 "Mentor" 2nd processor (bottom)

The socket on the bottom connects the 68008 2nd processr to the BBC Micro. The BBC Micro's 6502 CPU is removed and a ribbon cable is plugged into the socket and the socket on the bottom of the 68008 2nd processor board.

The Cumana 68008 2nd processor had its own disc controller and ran OS9 from its own floppy drive. It shipped with the standard OS9 utilities and applications.

The board was developed with Vivaway Ltd who were the UK agents for Microware Systems Corporation who developed OS9. Further details of OS9 can be found on Wikipedia.

These boards were kindly donated by Philip Jones who used to work with one of the developers.

Here is a copy of the Installation Guide for the BBC Upgrade .
Here is a copy of the Cumana 68008 2nd processor circuit diagram .
Here is an article from Acorn User in Nov 1985 titled "Cumana launch 16-bit processor "