easy eprom questions

Hi Group,

I am a foolish hobbyist who would like to program 27XX eproms sometime
within the next year.

First question: I pulled what I think is an eprom from a board. The
chip is an OKI M2764Z-N. It has no quartz window which causes
confusion. I assumed so far that all 2764s were eproms. Can it be an
eeprom?

Second question: I plan on building a simple eprom burner for 2764s,
27128s, 27256s. I would like it to use LPT1 under DOS (for simplicity's
sake). Are there any projects on the web I can study to help me in my
journey?

Third question: which junky old electronics am I likely to find these
eproms in?

Thanks,

 

Second question: I plan on building a simple eprom burner for 2764s,
27128s, 27256s. I would like it to use LPT1 under DOS (for
simplicity's
sake). Are there any projects on the web I can study to help me in
my
journey?

You start with Google.

Er. Ok I'm finding more. Ignore my gravely insulting use of newsgroups

 

[Peter Bennett]

On 2 Jan 2005 00:04:45 -0800, micologist@gmail.com wrote:

John Popelish wrote:

You should look for a small ultraviolet eraser, also.

I was thinking of building one with a germicidal lamp. If I can find a
local supplier and they are cheap.

Thanks,

I suggest you use EEPROMs rather than UVPROMs - no need to worry about
the UV lamp, or waiting for the chips to erase.

I've used Microchip 28C64 EEPROMs as replacements for 27C64s during
program development.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
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Vancouver Power Squadron: http://vancouver.powersquadron.ca

 

[CBarn24050]

Subject: Re: easy eprom questions
From: Rich Grise richgrise@example.net
Date: 02/01/2005 21:58 GMT

Second question: I plan on building a simple eprom burner for
2764s,
27128s, 27256s. I would like it to use LPT1 under DOS

What for? flash is easier, faster, pin compatable and cheaper.

 

CBarn24050 wrote:

Second question: I plan on building a simple eprom burner for
2764s,
27128s, 27256s. I would like it to use LPT1 under DOS

What for? flash is easier, faster, pin compatable and cheaper.

I guess it all started when I was found an old atari 800xl. I peeked
inside and saw that everything was socketed. I wanted to mod it
immediately. I found some documentation (on the net) from it's heyday.
It all deals with eproms. I assume eeproms weren't available/or cheap
at the time.

I'll look for eeprom (flash) alternatives then.
Thanks for the wack in the head

 

[John Popelish]

CBarn24050 wrote:

Subject: Re: easy eprom questions
From: Rich Grise richgrise@example.net
Date: 02/01/2005 21:58 GMT

Second question: I plan on building a simple eprom burner for
2764s,
27128s, 27256s. I would like it to use LPT1 under DOS

What for? flash is easier, faster, pin compatable and cheaper.

I agree. EPROMs are obsolete.

--
John Popelish

 

Peter Bennett wrote:

I suggest you use EEPROMs rather than UVPROMs - no need to worry
about
the UV lamp, or waiting for the chips to erase.

You're right. I should do everything possible to preserve my eyesight.

I've used Microchip 28C64 EEPROMs as replacements for 27C64s during
program development.

Thanks for the tip. I'll look into that.

 

[Mark Zenier]

In article <1104643667.683300.235130@z14g2000cwz.googlegroups.com>,
<micologist@gmail.com> wrote:

Hi Group,

I am a foolish hobbyist who would like to program 27XX eproms sometime
within the next year.

First question: I pulled what I think is an eprom from a board. The
chip is an OKI M2764Z-N. It has no quartz window which causes
confusion. I assumed so far that all 2764s were eproms. Can it be an
eeprom?

You're out of luck, unless you can find a friendly high energy
physics lab that has an accelerator that can produce enough stray
x-rays to erase them. ;-) These are OTP (One Time Programming) EPROMS.
The most expensive part of the EPROM is/was the fancy package with
the quartz glass window.

Second question: I plan on building a simple eprom burner for 2764s,
27128s, 27256s. I would like it to use LPT1 under DOS (for simplicity's
sake). Are there any projects on the web I can study to help me in my
journey?

Steve Ciarci's old Byte magazine Circuit Cellar project books.
Or Steve Walz's web/ftp site.

Third question: which junky old electronics am I likely to find these
eproms in?

Older IBM clone keyboards. The ones with a XT/AT switch on the
bottom. Circa 1985 they were usually a 8031 or 8039 single chip
microcontroller with an external 2764 EPROM. Some used 8748 EPROM
based microcontrollers, too.

If you have to punt and buy some, try Jameco or B&G Micro.

Mark Zenier mzenier@eskimo.com Washington State resident