PCA9956B reset behaviour - Not loading default values after I2C software reset

[Copeland]

I am writing to seek assistance with your product, the PCA9956B LED driver. I am currently using it with an STM microcontroller and encountering the following two issues:

Error Signals When Not Expected: During robustness testing, I disconnected the I2C BUS. Subsequently, the Error bit in the MODER2 register was set to HIGH. My understanding is that this should only occur if there is an open or short circuit in one of the LEDs.

Driver Sometimes Doesn't Respond: In similar tests, the LED driver occasionally stops functioning correctly. It appears to acknowledge commands send via I2C (as indicated by the ACK on the I2C bus), but it does not execute the commands as expected.

When sending a software reset, the device ACK's the command, but the registers are not set back to default.

Neither hardware nor software resets consistently resolve this issue.

Could you please provide insight into why these issues are occurring and how I might resolve them?

[JozefKozon]

Dear Robert,

please share your schematic with voltage levels and part values. Please share a scope from an oscilloscope or from an logic analyzer when you are sending the SWRST command.

Do you see this behavior on one PCA9956B? Or have you tested more pieces with the same results? If more, on how many PCA9956B do you see this issue? Please confirm the source of the PCA9956B. Have you purchased all of the PCA9956B from one of our authorized distributors?

With Best Regards,

Jozef