SK-AM64B: CP2105 not working

Vincent,

can you please describe the steps you did and also share some images which brings you to the conclusion that the EVM is dead.

Regards

Anshu

Hi Anshu,

Good Day. Please see below the response of our customer to your reply. Thank you very much.

Upon the arrival of the SK, I plugged it in but quickly realized the UART interfaces weren't showing on my host computer. I realized that LD18 does not turn on, indicating the CP2105 VCC is not present. By applying a temporary solder bridge between the main board 3V3 and the CP2105 3V3 the UART interface works.

Best Regards,

Ray Vincent

Hello Ray Vincent

Please remove the 3.3V bridge made for testing the CP2105.

The CP2105 is expected to be powered by the external USB interface. Can you confirm the power is available at the output of the USB connector. You can measure across D3 or the cap.

regards,

Sreenivasa

Hi Sreenivasa,

Good Day. Please see below the response of our customer to your reply. Thank you very much.

I know the CP2105 is intended to be powered by USB. I removed the bridge, connected a USB cable to J11, and measured around C86: 5.1V.

Best Regards,

Ray Vincent

Hello Ray Vincent

Thank you for the input.

Can you please request customer to check if they see the VDD_CP2105 and VBUS_USB_CP2105 near to the IC.

Could you also please ask customer to elaborate how they did the bridging? 

Regards,

Sreenivasa

Hi Sreenivasa,

Good Day.

VDD_CP2105 is 0V.

VBUS_USB_CP2105 is 5.1V.

Meaning the CP2105 internal regulator doesn't work. The solder bridge I placed connected VDD_CP2105 and VCC_3V3_SYS together.

Best Regards,

Ray Vincent

Hello Ray Vincent

Thank you for the inputs.

Let me check the case and update you.

Please expect some delay.

Regards,

Sreenivasa

Hi Sreenivasa,

Good Day. Is there any update on your side? Please advise. Thank you very much.

Best Regards,

Ray Vincent

Hello Ray Vincent

Good morning.

I am checking internally on the steps forward and will update you once i hear back from the team internally.

Regards,

Sreenivasa

Hi Sreenivasa,

Good Day. Any updates? As our customer follow-ups his query? Thank you very much.

Best Regards,

Ray Vincent

Hello Ray Vincent

Thank you for the follow-up.

FYI, this is a case where customer applied the supply to an output of a regulator which is not recommended.

I am checking internally on how best we could support the customer.

I should have some updates In a day or two.

Regards,

Sreenivasa

Hello Ray Vincent

Please suggest customer to go ahead and initiate the RMA process. The board is expected to be shipped back to Mistral - EVM manufacturer for further analysis.

/cfs-file/__key/communityserver-discussions-components-files/791/Customer-Return-Process-_2D00_-Hardware-Applications-_2D00_-Confluence.pdf

Regards,

Sreenivasa