Scor­pio News

  

January–March 1987, Volume 1, Issue 1











Page 42 of 63











Review of the MAP-80 Video/Floppy Controfler by P.D. Coker

Over the past few years I have been using an 80-308 curd provides the video and floppy ait

Ie/sve and FDC cards.” The ‘Supplied ae a kit which was well documented and pi Satlefactorily after a simple setting up of the FDC with an oscilloscope. The Wrc is supplied ae a kit or ready-bulit, either as a video controller or floppy Aisk controller only, or with both facilities implemented; » keyboard interface land video switch are optional for the video-only version but are included in the Complete VIC,

versions and. wai (ed, and worked

\uaT 17 ComsIsTs oF

The VFC card can be used in 3 ways: as a combined video and floppy disk controller, as s video controller only or as a floppy disk controller (for 5.25* or smaller driver only)

‘The video 1ory-mapped 80 column by 25 row display with « set; there ie. facility to ewitch an ‘the VEC, and the video output

5 Dor 8 bit ASCIT

keyboard can be Hinverted’ character a games

re

‘the floppy disk controller will cope with any make of drive, apart from Some criticism har been levelled at MAP Systems for this, buc few users will find {t a limitation. Also included is 4k of RAM, 2X of which Le used for the display and the rest by the operating software ‘It uses a total of 16 ports which are link-selectable, enabling the User to choose any group of adjneent ports from CO to EP: the defaule port allocations are from £0 to EF but Rlternatives are tuggested

‘The board contains « standard 6845 CRT controller and # 2797 FDC; unlike the Gemini Ivc/svc, there is no on-board Z80 and the 279: ‘more sophisticated Version of the i797 disk controller used on the Gemini GM829 FDC/SASI board, and Is from the same family a the 2793 disk controller used on the more

Gemini cMaeo POC/SCSI controller. ALL this Le contained on a sin board which plugs directly into the usual 80-BUS conne

ff’the kit is constructed and

will do thie for you for a enall fee, but che construction Gnd the average person would find iittle difficulty in producing « working version.

There is a significant design difference between the two types of video Controller: the Gemini IVC and SYC have a 200 incorporated on the board (290A in the case of the {VC and a Z60B which uns at Gus in the SVC) Effectively, these are single-board, highly specialized micro-computers, vhereas the VFC has no microprocessor included and thus forgoes the benefite of paraliel-procestin For many applications this will not be « great disadvantage since the VEC foftwace ix quite sophiseicated and carries ut the task of interfaciag between the VFC and CPU very efficiently so that most users would not be aware of any difference in the perfor! veTthe sve, running at 6Hiiz, Dave Hunt’s brief test ( re on-board memory pt ‘s0 uses a high quality version of the 6865 (tte performance iv degraded if the Standard veraion ts used).


This is an OCR’d version of the scanned page and likely contains recognition errors.











Page 42 of 63