Following the success of the
MAP 256k RAM
Systems Ltd is pleased to announce the launch of a new product
for the Nasbus/80 Bus. This is the MAP
CONTROLLER) which can be used with either the Nascom or Gemini
range of computers.
The original object of the new card was to provide the
Nascom user with a cost effective option of an industry standard
80 column screen. In order to keep the cost to a minimum it was
decided not to provide high resolution graphics but to support
the simple character set that has been so successful on the
standard Nascom. An on board character generator provides the
standard 256 character set but it is possible to select 128
characters with inverse video under software control.
Facilities are provided for a second EPROM character
generator which can be switches under program control. On board
software has also been incorporated, providing full screen and
keyboard handling together with a CPM boot, making the card
extremely easy to use. During normal operation the screen is out
of the T80 memory map and is switched into the map only when
video RAW access is required. Simply, the sequence of events is
as follows. Page in the video card (at any 4k boundary selected
under software control) Call onboard relocatable software and
then page the card back out again. The result is a fast memory
mapped screen that occupies no space in the memory map,
enabling, for example the implementation of a full 64K CP/M.
Clearly this exciting new product cat be used in many
applications, for example it is possible to run a complete 64K
CP/M computer with only two 8″ by 8″ cards by using the MAP VFC
card and a Gemini
CPU card (and don’t expect it to remain
the only memory mapped CPU card for the 80 BUS).
As the project progressed it became apparent that there was
plenty of space available and we are therefore able to offer the
following optional extras. A KEYBOARD PORT for either 7 or 8 bit
parallel ASCII keyboards with either positive or negative strobe
has been incorporated on the card. Light pen facilities are
available if required. For the Nascom owner a special VIDEO
SWITCH can be fitted which would allow the user to select an
alternate screen (eg original Nascom screen) under software
Finally, the most useful feature that we have incorporated
is a FLOPPY DISC CONTROLLER. The controller will support any 5″
drives in either single or double density. It is totally
software compatible with the Gemini
FDC and uses all the
same control ports etc.
AVAILABILITY --- The first complete cards will be
despatched in the latter part of January and we expect the
first kits will be despatched during late February. If you wish
to order please complete the order form and return it to us with
your cheque or postal order. We are prepared to receive orders
for kits but they will only be despatched after we have cleared
the back orders for the built product.
MAP 80 SYSTEMS LTD.,
___ _______ ____,
LONDON __ __.