Damaged PCF85363ATT?

[Ivan78]

Hello,

I am experiencing some strange problems with PCF85363ATT. The device has a capacitor instead of a regular battery to keep the power up for some time.

Basically I can communicate with the device, I get the I2C ACKs, I can write and read back the control registers (eg 0x25...).

I am using the device pretty much in the default condition, I just change the oscillator capacity register to 0x02 (12pF). I can see a perfect 32kHz signal on the INT pin (clock out).

I write the time and wait a few seconds, read the time and the time did not increase. Sometimes I read back the time and it is exactly the same, somtimes I read back all 0s.

I know it sounds like a I2C issue on my part, but the signals look very good and I get all the ACKs from the device.
Above all, the RTC used to work fine.
It's like it is somehow partially damaged, I don't get.

Any ideas?

Thanks to all,
Ivan

[guoweisun]

You can do cross test using the issue board's RTC into good board,vice versa.

Then check the test result/

[guoweisun]

1: please share with your schematic

2:how many board has this issue? if change other RTC what will happen?

[Ivan78]

Hi and thanks for the reply.

Schematic as simple as that, SCL and SDA go directly to the uC pins.

I checked the Vbat and it is always clear without glitches,

I stated before that the RTC used to work and stopped working correctly at a certain point, but now I have the doubt that the item that I am investigating now never worked, since I've been switching between several boards that might have confused me.
I have now this issue on 5 boards out of 10, I'm starting to think that we might have bought a buggy set of PCF85363ATT. You never know during this crazy period!

Thanks again,

Ivan