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Old 28th Mar 2021, 12:09 am   #277
Slothie
Octode
 
Join Date: Apr 2018
Location: Newbury, Berkshire, UK.
Posts: 1,287
Default Re: I found it! A very sorry looking MK14.

Quote:
Originally Posted by circuitryboy View Post
I hadn't seen that "Christopher" 2014 posting before.
In 2019 I showed that the Tesla PROMs (MH74-188, -S287, and -S571) had those similar part numbers and used exactly the same programming protocol as the earliest TI (SN74-) PROMs. But TI didn't have a '571.
The TI data shows the '287 programs 'the other way'. I'm not sure why "Christopher" believes the MH74S287 does not. He wasn't using them, just warning to check the datasheet.
Later TI PROMs have different prefixes and require other/more voltages in their programming sequence.
How far back do the Tesla chips date? Certainly to 1989.
Remember that rogue "MH74S571" page in German which confusingly indicated 21V?
It's actually a page of Fairchild 93438 from a databook published in DDR, 1989. The MH74S571 was described immediately before that (without programming details). And somebody didn't notice the change.
A year ago I translated a data sheet from Czech from the Tesla manual that details the programming procedure in this thread: https://www.vintage-radio.net/forum/...d.php?t=146388 (first post) I have since received details from an actual Czech with experience of programming them that confirms my translation (transliteration?) was broadly correct, along with some designs that I am not at liberty to divulge but I can use to guide my own design.
AFAIK although there are similarities, Tesla 74S571 PROMs need specific programming that is different in the details. One of my many projects in my "in progress" list is a Arduino based programmer for Tesla MH74S571 PROMS.
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