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shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
for me it is more easy to draw with pen at the paper. maybe i'm already outdated Very Happy
Post 11 Sep 2008, 10:41
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demiourgos



Joined: 10 Feb 2008
Posts: 11
demiourgos
shoorick wrote:
for me it is more easy to draw with pen at the paper. maybe i'm already outdated Very Happy
... or simply underdeveloped.
Post 11 Sep 2008, 16:24
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shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
to use 8-bit rom at 16-bit or 32-bit bus source image can be splitted with the little program i wrote yesterday


Description:
Download
Filename: romsplit.0.1.1.1.zip
Filesize: 9.04 KB
Downloaded: 413 Time(s)


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Post 09 Oct 2008, 06:07
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shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
hi again here! Wink

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 Wink it works Wink

Image

Image

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

Image

Image

regards!

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Post 11 Dec 2009, 05:57
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edfed



Joined: 20 Feb 2006
Posts: 4225
Location: 2018
edfed
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!
Post 11 Dec 2009, 15:20
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shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
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 Wink )

regards!

Image

Image
Post 14 Dec 2009, 06:04
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16901
Location: In your JS exploiting you and your system
revolution
That's why we have FLASH now days.

EPROMs? What are those? WinkRazz

Don't forget to shield your eyes from the UV light.
Post 14 Dec 2009, 06:15
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shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
Quote:

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

Cool
Post 14 Dec 2009, 06:27
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shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
shoorick wrote:
minimizing soldering
here is examples of usage single obvious chip 74LS138 as ROM selector:

Image

it is applicable for 27512, 27256 and 27128 types, for roms of less size additional chip will be needed.
-----------------------------------------
hope, nobody has build this yet Very Happy
swap A16 and A18 lines at diagram!


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

Image

Image

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

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Post 20 Jan 2011, 13:37
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