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PC (Program Counter) corruption after power off | Cypress Semiconductor

PC (Program Counter) corruption after power off

Summary: 3 Replies, Latest post by H L on 20 Aug 2013 12:31 AM PDT
Verified Answers: 0
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sego's picture
43 posts

After 2 weeks of work the chip suddenly failed after power off.
PC jumps to strangle locations. The whole flash is write protected. The only thing I occasionally write is EEPROM.

user_1377889's picture
9249 posts

As far as I know, most devices fail when they are switched On!

I would suggest to read-out the flash and compare it with the desired hex. When you have debugging capabilities integrated to your board you even may inspect the memory contents.



user_14586677's picture
7646 posts

Suspect as always is tranients on I/O pins that inject charge into the

substrate, and potentially corrupt FLASH cells. Or transients on Vdd

that exceed gate ox breakdown. Best way of detecting a condition like

this is a DSO set to trigger on something like this -


Vss - .7V >  Vtrig > Vdd + .7V


and look at key interface pins talking to loads than can generate

transients, like a relay, a MOSFET driving a relay (transient feedback

thru Cgd). Set up jig to cycle power, and enable DSO on signal that

triggers power up and down.


This is vary tedious to find, patience is a virtue.


Also in general power supply sequencing, make sure PSOC comes up

before any I/O loads do. If you cannot guarentee that make sure all pins

clamped by zener arrays, avaialable from On Semi, Vishay, Fairchild to

name a few.


Regards, Dana.

user_460349's picture
1362 posts

How do you find the PC corrupted?

Would there be some cases where your EEPROM value is out of your expected range and your program perform not as you expected?



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