Who remembers EPROM?

RE: Who remembers EPROM?

neilk — Sun, 07 Nov 2021 13:37:42 GMT

I have been searching my disorganised archive, on and off since you first posted and finally located some chips. hence my late comment.

In the early 80s through to 1990, I was a external consultant to a small company that manufactured echo sounders, logs and wind speed indicators for (mostly) pleasure boats. We developed the first echo sounder using the MCS- 8048 microcontroller which was one time programmable. A pain during development - if it had a bug, you threw it away!

We moved on to 8748 chips which were UV eraseable. I had all the kit at my house and I used to program the production chips in batches of 100, cover the window with an identification label, and post them to the factory (200 miles away).

Eventually, we developed a system whereby I burnt the code into a 2764 EPROM, with an identification label covering the window, and posted that to the factory. They then copied the code into the target micro controller - 8031, I think, by then.

I have samples of most of the chips we used, including a set for the last instrument I worked on, as follows:

ver 1.0 12 July 1990

ver 1.1 13 August 1990

ver 1.2 12 October 1990

ver 1.3 17 November 1990

ver 1.4 26 November 1990

I assume version 1.4 went into production, but I haven't located any documentation to support that. I still have two 5 1/4" floppy disk which purport to carry the code, but no way of reading them. Somewhere, I also have a listing of the code.....somewhere!

Neil

RE: Who remembers EPROM?

ralphjy — Fri, 22 Oct 2021 21:46:42 GMT

We used UV eraseable eproms to store configuration data for the computer peripherals that we designed.

I found my old UV eraser in with a bunch of old computer stuff.

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-b39f948a-0608-4bf7-acca-b59847e28cee/2047.contentimage_5F00_216679.jpg:620:465]

I also found a sample box of ST parts circa late 80s.

[View:/resized-image/__size/298x328/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-b39f948a-0608-4bf7-acca-b59847e28cee/7245.contentimage_5F00_216680.jpg:298:328][View:/resized-image/__size/293x327/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-b39f948a-0608-4bf7-acca-b59847e28cee/3531.contentimage_5F00_216681.jpg:293:327]

These were byte wide, so 4kx8 and 32kx8. I must have used the 1 Meg eprom somewhere [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-b39f948a-0608-4bf7-acca-b59847e28cee/4111.contentimage_5F00_938.png:16:16].

[View:/resized-image/__size/620x619/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-b39f948a-0608-4bf7-acca-b59847e28cee/7343.contentimage_5F00_216682.jpg:620:619]

RE: Who remembers EPROM?

DAB — Thu, 21 Oct 2021 18:07:53 GMT

I started with the 2704 versions with only 4 K bits.

They were so sensitive to electrostatic discharge.

I could usually destroy one by just walking across the floor and picking one up.

DAB

RE: Who remembers EPROM?

Gough Lui — Thu, 21 Oct 2021 08:56:49 GMT

I certainly remember them ... I even went to some way to try and collect some purely for the visual aspect -

https://goughlui.com/2016/05/22/tech-flashback-the-beautiful-eprom-chip-collection/

Unfortunately, no microscope here, but a macro lens gets me a little bit closer.

I did try sunlight erasure ... almost forgot about it:

https://goughlui.com/2016/09/11/experiment-time-to-eprom-erasure-by-uv-lamp-sun/

As for real chips, there were a few from a prototype research run that I decided to encase in resin for a bit of art -

https://goughlui.com/2020/06/08/salvage-project-ceramic-package-chip-art/

Chips are plenty beautiful even if you don't understand microelectronics ...

- Gough