PCA9955 led driver issue with Fault test feature

[gabriele_fallini]

Hello Community,

 I'm facing an issue trying to use the Fault test feature of the PCA9955 driver.

According with the Datasheet, the test starts when Bit6 of Mode2 register is set.

And so far so good. Then you need to check if that bit is set to 0 indicating that the Test procedure has been completed.

Im my case that bit is always 1. It is never set to 0 by the driver itself.

Please,could you support me on this issue?

Thanks a lot

[gabriele_fallini]

Sorry Jozef,

 I really apologize. I am using the 9955B (my previous description was for 9955)and the way to deal with led error detection is totally different.

So nevermind about my previous question.

Thanks for your quick support.

Best Regards

[JozefKozon]

Hi Gabriele,

no problem at all. It was also my fault. I apologize for that. I have checked the datasheet for the PCA9955B instead of the PCA9955. But at least I gave you hint for the correct datasheet. 

With Best Regards,

Jozef

[JozefKozon · Accepted solution]

Hello Gabrielle,

could you please provide more details of your test? Did you try to write 1 to the Bit 6, the ERROR bit in the MODE2 register? If so, this is not possible, the ERROR bit is read only and when is set to 1, it indicates, that there is some hardware issue on one or more of the LED outputs. 

There are EFLAG0 to EFLAG3 registers, where you can specifically check on which LED output or outputs is the fault and what type of fault is on the output or outputs. Please check the EFLAGx registers to find out what type of fault is on the LED outputs.

With Best Regards,

Jozef