74*393 vector test bug

General topics relating to devices and programming
JudgeBeeb
Posts: 3
Joined: 24 Sep 2018 11:41

74*393 vector test bug

Postby JudgeBeeb » 27 Sep 2019 19:45

The algorithm for testing 74*393 devices appears to have a bug. I have two different batches of new 74LS393 devices and they all failed the vector test in the same way. (And they work just fine in circuit.)

I know that this is not a killer feature, but it would be nice if this could be corrected.

Dataman (Neil Parker)
Posts: 789
Joined: 10 Nov 2011 09:51

Re: 74*393 vector test bug

Postby Dataman (Neil Parker) » 30 Sep 2019 09:20

Hello JudgeBeeb,

Thank you for posting in our user forum. Can I ask you to recreate the situation that you describe where our software detects a fault and then use the (Help > Create problem report) feature and email the resulting ZIP file from your desktop to support@dataman.com for analysis.

Best regards,

Neil Parker
Dataman Programemrs

JudgeBeeb
Posts: 3
Joined: 24 Sep 2018 11:41

Re: 74*393 vector test bug

Postby JudgeBeeb » 30 Sep 2019 13:53

Dataman (Neil Parker) wrote:Can I ask you to recreate the situation that you describe where our software detects a fault and then use the (Help > Create problem report) feature and email the resulting ZIP file from your desktop to support@dataman.com for analysis.

I will try to do that this week.

JudgeBeeb
Posts: 3
Joined: 24 Sep 2018 11:41

Re: 74*393 vector test bug

Postby JudgeBeeb » 01 Oct 2019 07:34

I have sent in the file this morning.

Dataman (Neil Parker)
Posts: 789
Joined: 10 Nov 2011 09:51

Re: 74*393 vector test bug

Postby Dataman (Neil Parker) » 06 Nov 2019 14:40

Hello JudgeBeeb,

We received your device and after testing we observe that the 74LS393 really does show an error.

The background of "why" is pretty complicated, but in short: the pindriver construction in our programmers are focused on programming and have some limitations for "IC testing" purposes. Although we are doing "everything that can be done", in some special situations (like when treating the pin PU/PD and reading the pin level at the same time) it can happen that some narrow spike appears.... and sensitive devices like asynchronous counters, might respond to this - and the result is a false detection (in some cases - the HC version is OK).

Sorry, we are not able to improve situation, we can only remove the 74xx393 from the IC testing system.

Best regards,


Neil Parker
Dataman Programmers


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