ivan@rzsin.sin.ch (Ivan D. Reid) (05/09/89)
I finally got my hands on a copy of the 5/89 'ST 68000er Magazin' last night and struggled through the article on increasing the display size of the ST screen. It's a hardware kludge to keep the display enable (DE) signal to the MMU and shifter chips active longer, thus displaying into the overscan on all four sides. It's just a simple little DTL circuit that only disables DE when either HSync or Vsync are low, plus a switch to restore to the original configuration when needed; a switch, a transistor, 2 resistors, 2 diodes and a condensor, plus 3 wires and a cut in a PCB trace. Apparently there are a couple of other mods that might need to be made for very old STs. There seems to be at least two versions of the software; one is a GFA-Basic programme to modify "Ihre Original-Beta-TOS-Diskette"(!) so that Beta-TOS comes up in the larger sized modes, and another to be put in the \AUTO folder for use with ROM-TOS. The latter is given as a type-in programme 2.8Kb long, but they're both separately available on a diskette (DM30). This diskette is a bit amusing to me -- it also includes V1.25 of HiSoft's DevPac, which has been superseded by V2.0. Last month in England I bought a mag with disk included, also with the DevPac, but they wanted 25 quid for the documen- tation; 68000er printed 4 pages of documentation but wants DM30 for the diskette!!! So for the cost of two mags... Anyway, next month 68000er will print more stuff on their "Hyperscreen", including a list of programmes that work with it. If I've made any gross errors in the above, I hope one of our German-speaking correspondents will correct me. ivan
dac@ukc.ac.uk (David Clear) (05/11/89)
In article <250*ivan@rzsin.sin.ch> ivan@rzsin.sin.ch (Ivan D. Reid) writes: >(a little) >.... It's a hardware kludge to keep the display enable (DE) signal to >the MMU and shifter chips active longer, thus displaying into the overscan on >all four sides. >(then lots more) Has anyone tried this in the colour modes? I've seen demos where overscan is achieved in software by playing with the 50/60Hz register, but uses up an awful lot of time to do the side borders. Overscan in colour sounds very interesting. -- % cc life.c | David Clear <dac@ukc.ac.uk> % a.out | Computer Science, University of Kent, Segmentation fault (core dumped) | Canterbury, England.