SAM7S64 Rev B to Rev C Migration

sandeep2505 · **Joined:** Fri Mar 09, 2012 1:21 pm **Posts:** 3

Hi,
We are using AT91SAM7S64B in our project, with this processor we have completed our hardware design and firmware. But now Rev B of this controller is obsolete and Atmel has intrduced Rev C of this controller. While using Rev C of AT91SAM7S64 we are facing below problems.

1) Internal ADC failure: Some times it is observed that ADC counts are coming 0.
2) Debug port failure: Some time junk data is coming on terminal.
3) Cross communication (SSC Communication) failure
4) GPIO as output failure in one chip: some times pins not toggling properly.

We have proven firmware and harware with Rev B however there are these listed issues with Rev C.

Does anybody has any idea; what special care we need to take while migrating from Rev B to Rev C of AT91SAM7S64?

Thanks in advance,
Sandeep Patil

CptTitanic · **Joined:** Sat Oct 30, 2010 6:04 pm **Posts:** 784

Seem to recall you need to look at the PLL and FLASH timings/settings.

gerhardf · **Joined:** Thu Dec 02, 2004 2:28 pm **Posts:** 504

according to datasheet rev. L, sam7S64 Rev. C doesn't have an errata entry regarding EFC (flash timing).
but maybe the flash timing of the board is above the limit and was working with rev. B coincidentally.

regards
gerhard

przemekbary · **Joined:** Fri Mar 09, 2012 1:34 pm **Posts:** 68

Hi!
I'd rather go for improper soldering - short-circuited or floating pins. That's what I know of after soldering a few dozens of them. Sometimes, there happen strange things - you shake the circuit or put upside-down and it changes its behavior -- all due improper electrical contact.

How many chips have you tested that exhibit these symptoms?

sandeep2505 · **Joined:** Fri Mar 09, 2012 1:21 pm **Posts:** 3

przemekbary wrote:

Hi!
I'd rather go for improper soldering - short-circuited or floating pins. That's what I know of after soldering a few dozens of them. Sometimes, there happen strange things - you shake the circuit or put upside-down and it changes its behavior -- all due improper electrical contact.

How many chips have you tested that exhibit these symptoms?

I have stested this IC on 5 boards and all boards are having different issues. But I dont have any doubt on soldering side as on the same board we have reaasmbled the B version controllers which worked properly.

sandeep2505 · **Joined:** Fri Mar 09, 2012 1:21 pm **Posts:** 3

gerhardf wrote:

according to datasheet rev. L, sam7S64 Rev. C doesn't have an errata entry regarding EFC (flash timing).
but maybe the flash timing of the board is above the limit and was working with rev. B coincidentally.

regards
gerhard

Hi, I am from the hardware background, so can you please elaborate related to flash timing, so that I can look into this in more details.

przemekbary · **Joined:** Fri Mar 09, 2012 1:34 pm **Posts:** 68

Hi
Then it seems a hardware problem.
1) Change the quartz for slower or different one
2) Change the operational frequency for slower
3) Increase FLASH waiting cycles in the FLASH controler
4) Check if the voltage on VDDCORE is stable

Let us know about the progress as I am also facing a new batch of circuits based on 7S64.

SAM7S64 Rev B to Rev C Migration

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