EPROM Windowed PIC's - Page 1
Forum section: electronics / general

author: Unknown
author_rank: Unknown
timestamp: July 21, 2013, 06:48:48 pm
content: Found these last night whilst sorting out some old chips so that I could find them again if need be.

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 21, 2013, 07:13:32 pm
content: They're a beauty, but I don't regret that flash memory won the race. I remember the erase time of eproms (15 minutes?) which totally killed your productivity while debugging.

author: Unknown
author_rank: Unknown
timestamp: July 21, 2013, 07:16:03 pm
content: lol yeah, it was awful having to wait for the erase cycle to complete, took flippin ages to debug the firmware. I just about remember using them.

author: Dataforensics
author_rank: Unknown
timestamp: July 21, 2013, 07:22:11 pm
content: Ah what you needed was a dataman strobe eraser, only took around ten seconds. I still have one and its a device I was always a bit scared to use as it could probably blind you in seconds.Woops, just looked them up and see they are not recommended for microcontrollers.

author: Vernon
author_rank: Newbie
timestamp: July 21, 2013, 07:25:15 pm
content: Quote from: Pippy on July 21, 2013, 06:48:48 pmYes! things of beauty. They belong in a museum

author: David_AVD
author_rank: Super Contributor
timestamp: July 21, 2013, 11:10:24 pm
content: Quote from: PA0PBZ on July 21, 2013, 07:13:32 pmI used to have 3 windowed chips when developing code. One in the board, another in the eraser and a third one cooling down after being erased.

author: EEVblog
author_rank: Unknown
timestamp: July 22, 2013, 04:57:54 am
content: I've still got several windowed PIC's somewhere. Ah, the memories...

author: free_electron
author_rank: Super Contributor
timestamp: July 22, 2013, 02:25:39 pm
content: What is this ? A bunch of crotchety old men reminiscing about the good old days ?Sheesh...In my time i had to walk two hours to get to the internet. In winter even through the snow ! And now ? The click and -wooft- everything is there ... Mumble mumble...

author: daveshah
author_rank: Unknown
timestamp: July 22, 2013, 02:38:06 pm
content: I've always wondered if it would be possible to specifically program bits using a very narrow beam laser

author: free_electron
author_rank: Super Contributor
timestamp: July 22, 2013, 02:44:53 pm
content: The laser would erase them... You need an electron beam to charge the gate..

author: AlfBaz
author_rank: Super Contributor
timestamp: July 22, 2013, 03:11:24 pm
content: Erasers... You blokes were spoilt, I stuck mine on the window sill for day or two

author: andersm
author_rank: Super Contributor
timestamp: July 22, 2013, 03:20:26 pm
content: Quote from: free_electron on July 22, 2013, 02:44:53 pmThose kinds of methods have been used to reset code protection bits in decapped devices.

author: free_electron
author_rank: Super Contributor
timestamp: July 22, 2013, 03:59:48 pm
content: Jep. That's how it is done. Decap , flash the fuse bit. Dump...There are specialized companoes that have maps for almost every processor where the bits are.Its not hard to find. Buy blank chip , set fuse , probe around with an ebeam to see where the charge is. Takes a few hours the first time. Write down coordinates. Next chip takes less than a minute to do.

author: nctnico
author_rank: Super Contributor
timestamp: July 22, 2013, 07:56:43 pm
content: Quote from: AlfBaz on July 22, 2013, 03:11:24 pmIIRC I also have a windowed PIC somewhere. Many years ago I build a ^Canal+ (pay TV) decoder from a diagram on internet. Because there where several software versions I bought a PIC with a window so I could erase and re-program.

author: lapm
author_rank: Frequent Contributor
timestamp: July 25, 2013, 06:36:35 am
content: Quote from: PA0PBZ on July 21, 2013, 07:13:32 pmThats why you used more then one chip while developingRemember developing some code at school, used 4 chips while developing. Erase some, have couple still to test your code.Thank God we have flash memory now, much much easier and faster.

author: ben_r_
author_rank: Frequent Contributor
timestamp: July 29, 2013, 09:27:09 pm
content: Ha, I still have several of those too. I used to use the Dataman UV eraser too.

author: MrAureliusR
author_rank: Unknown
timestamp: August 09, 2013, 01:24:07 pm
content: The colour scheme for the PIC's on the right seems to be a popular one for EPROM based devices. I've got a couple old (70s) TI EPROMs that look identical. They still work! I don't have an eraser though - realistically how long does it take sunlight to erase them?

author: Niklas
author_rank: Frequent Contributor
timestamp: August 10, 2013, 05:35:03 pm
content: My boss was contacted a couple of years ago regarding a project he worked on in the 1980s. The machine, a welding robot, had started to do strange things and it turned out to be related to a corrupted EPROM. They had used paper sticker instead of a foil based sticker to cover the window. Sometimes the products live longer than you initially plan for. It turned out that my boss still had copies of the old firmware stored on floppy disks and get the machine back to work again.

author: Unknown
author_rank: Unknown
timestamp: August 11, 2013, 01:51:44 am
content: Hm...can you glue a UV LED on each EPROM-window and make a super slow SRAM from it?=)))