Tektronix SP232 eprom dump - Page 1
Forum section: electronics / repair

author: picburner
author_rank: Frequent Contributor
timestamp: July 20, 2019, 03:39:07 pm
content: I have a SP232, serial extended function module, for Tektronix TDR 1502B/C - 1503B/C which suddenly failed.After a search the fault would reside in the eprom U1016 (27C512) which probably got corrupted.Has anyone by chance done and has the dump of this eprom?Tek code should be 160-4978-00, Thanks.

author: picburner
author_rank: Frequent Contributor
timestamp: July 25, 2019, 04:07:11 pm
content: Apparently only two people around the world have this interface, one is me and the other does not frequent this forum.Unfortunately this eprom cannot be found on the usual sites like Tek Wiki, KO4BB, Electronicsandbooks etc.The eprom is not even on sale and there is not even on sale the complete interface (at least at a reasonable price).

author: _Wim_
author_rank: Super Contributor
timestamp: July 26, 2019, 04:05:38 pm
content: Hi, did you try to read-out your eeprom? What result did you get? You could try to reprogram a new eeprom with what you were able to read or maybe the stored content is ASCII and the corrupted characters can be guessed?

author: picburner
author_rank: Frequent Contributor
timestamp: July 26, 2019, 07:03:52 pm
content: yes, I tried to read the eprom but the data it contains is inconsistent.I tried to disassemble the content with dasm51 (the processor is an 80C31) but the asm source obtained does not make any sense.The certainty of the failure of the eprom derives from the fact that I tested all the other components on the pcb.Thanks anyway for your kind reply.

author: Per Hansson
author_rank: Unknown
timestamp: April 20, 2021, 03:25:37 pm
content: Hi picburnerI just got one of these off eBay, I have not tested it yet because I don't have a 25pin serial cable but it is in amazing condition.I have dumped the EEPROM with the guess that it is a AM27C512 because my programmer gives ID 0191 from the chip (AMD)I tried several times and at different speeds and always got identical dumps.

author: _Wim_
author_rank: Super Contributor
timestamp: April 20, 2021, 05:19:37 pm
content: Quote from: Per Hansson on April 20, 2021, 03:25:37 pmThanks for posting this. Is this a complex board, or would it be possible to replicate? Do you have any pictures of the PCB? I have been looking for one of these also, but so far no luck.

author: Per Hansson
author_rank: Unknown
timestamp: April 20, 2021, 05:55:09 pm
content: It's a really simple board layout wise.I took a picture earlier today that I was not going to post because I'm waiting for a lightbox to arrive.But since you asked here it is, no picture of the backside yet though, but it gives you an idea...

author: _Wim_
author_rank: Super Contributor
timestamp: April 20, 2021, 06:33:02 pm
content: That is indeed the kind of simplicity I was expecting (and hoping for). It should indeed be quite feasible to reverse engineer.

author: Per Hansson
author_rank: Unknown
timestamp: April 21, 2021, 05:15:36 pm
content: Here is a picture of the back too.The PCB measures 57.1 x 123.6mm

author: picburner
author_rank: Frequent Contributor
timestamp: April 21, 2021, 07:15:02 pm
content: Thanks for the report but I had already solved some time ago and I had posted the eprom dump on the ko4bb website.If you find it useful I attach the sp232s schematic here.Unfortunately the definition is low but that's all I have.

author: _Wim_
author_rank: Super Contributor
timestamp: April 21, 2021, 08:33:39 pm
content: Excellent info hereGoing to look closer at it this weekend.

author: _Wim_
author_rank: Super Contributor
timestamp: April 25, 2021, 08:27:42 am
content: Looking a bit more in detail to this, it seems the SP232 board is nothing more than a serial to parallel converter. This manual (https://www.tek.com/manual/sp232-user-manual) describes both the serial and parallel hardware protocol.Instead of trying to replicate an old 8051 micro board, I think it might be a better idea to just use an arduino or similar instead.

author: picburner
author_rank: Frequent Contributor
timestamp: April 25, 2021, 01:10:37 pm
content: Well, this circuit is as obsolete as the equipment it goes into.But it works and you can try to rejuvenate it a little by using smd components.Doing everything from scratch is certainly a good exercise and a nice pastime but if the aim is to use the device quickly, it is better to use what is already ready.

author: _Wim_
author_rank: Super Contributor
timestamp: April 25, 2021, 06:51:59 pm
content: No aim to use the device quicklyMaybe I am underestimating the job, but we will see. I can at least give it a try, we can always go back to try and replicate the Tektronix board.

author: lzqing
author_rank: Contributor
timestamp: March 28, 2025, 07:17:13 am
content: Hello! I just draw the schematic for SP232 module base on the limited information from this topic， FYI .Best RegardsAndy Lu

author: _Wim_
author_rank: Super Contributor
timestamp: March 28, 2025, 08:05:37 pm
content: Wauw, been a long time. Eventually lost interest in the project when I found an SP232 module on Ebay... Here is also a schematic I found online or received from someone here.