Micro­power

itself whenever the computer is on. The battery-backup takes over whenever the computer is switched off and the board can be removed, the page links reorganised, etc, etc. A very useful facility.

Link Block E (LKSE)     Nascom I/O decode.

This is provided for Nascom users who have not got the Nas-IO signal decoded anywhere else in their system. This provides all the decoding necessary for port FFhex.

All the link connections made on the board are done so using pieces of wire pushed into gold plated socket pins. Once you have decided how you ant your system configuring it is an easy matter (though fiddly at times) to cut the wire to appropriate lengths and link the pads. It is purely a matter of pulling out the appropriate links again in link blocks A, B and/or C to reconfigure the memory map, page layout and page-on-reset. As long as link block D connections, the power options, are not changed, the memory contents remain unchanged. I have carried the board around and left it unplugged for a couple of days without any corrupted data at all. The only thing that you have to be careful with is NOT placing the board on a conductive surface as this can short out the power lines and so cause the odd problem.

The possible uses for the board are endless. One application would be to use a page in Read only made to develope or modify another monitor system. I have used the board as two 16K pages, one of which contains Wordease and some printer driver routines and the other page purely as normal RAM. It means that I can switch on my machine on a morning, flip a port and then leap enthusiastically into my latest Wordease file without having to reload anything from tape. Easier to use than disc (and faster, and cheaper? and far more versatile than EPROMS.

The board runs at 4Mhz without wait states and if a partially populated board is purchased, any 6116 chips can be used as long as they do not draw more than 100 micro Amps each. Alternatively NMOS RAMs and EPROM can be put on the board but not connected into the battery-backed circuit.

In summary then, this is an excellent 8 by 8 board which is a viable alternative to an EPROM card as an. EPROM programmer/​eraser are unnecessary. It is easy to set up, very versatile and simple to use. A simple routine could easily be written to provide a menu driven system to select between the different pages and so utilities/​monitors/​programs.

Finally, many thanks to Mr. L. Opit of microcode for providing me with the board to review and helpfully answering all my questions.