for me it is more easy to draw with pen at the paper. maybe i'm already outdated

... or simply underdeveloped.

to use 8-bit rom at 16-bit or 32-bit bus source image can be splitted with the little program i wrote yesterday

hi again here!

here found another very interesting project: http://rayer.ic.cz/romos/romos.htm

have put 64k image into 27512 and tested it with extension board shown here above it works





even have tested my cyrillic forth, which was present on this pc on the hard drive





regards!

awesome project.

i'd like to be able to write (and erase with a UV spot) on roms directlly from the moded ISA card, is that a possible trick?

i have:
zip DIP supports.
various size UVPROMs
hole grid pcbs.
many components.
and maybe a UV led. (to make the eraser light).

i wonder if it is easy to do or very hard!

generally it is possible in-system eprom programming, but then you have to support separate switchable power supply 5->6.5V for the rom 2764-27512 while programming (it is possible to program them with 5V Vcc also, but then there is no guaranty for long persistent and stability of written data). also, there has to be 12.5V Vpp, which can be turn on-off even manually, except 2732 and 27512 - they receive Vpp through OE pin, thus it has to have electronic switch. what about erasing - also possible, but i'm using now UV lamp in power-saving package, and erasing takes hours and even tens of hours. it is bothering a little, but before i've been using bactericide lamp - it was much faster, but there was sufficient overheat of chips and lamp also, also i got many chips dead after such extreme erasing. (generally, all my eprom chips are used, so, there is no ensurance they were dead exactly because of erasing )

regards!

That's why we have FLASH now days.

EPROMs? What are those?

Don't forget to shield your eyes from the UV light.

if somebody still interesting with this, here is a rom card for 27512





(it can be placed into C0000h, D0000h or E0000h area with jumper)