BQ76PL455A-Q1: In what conditions does stacked devices get shutdown?

Hi Ritul,

There are several events that can cause the device to enter shutdown mode. These are listed in the device datasheet (www.ti.com/.../bq76pl455a-q1.pdf) section 7.4.1. "SHUTDOWN", pages 46 and 47.

Please review the modes to go into shutdown from the list in the datasheet mentioned above to make sure one of these is not the issue. Also, to focus on hardware debug first, please use the device GUI instead of the microcontroller software.

Best regards,
Leslie

Hello Leslie,

I have checked with the device GUI. In the GUI also, only 1 board is being detected. Second board does not get detected and addressed.
Bottom device is detected and working well. Top device is not detected till now.

Hi Ritul,

Thanks for checking. We can focus on the hardware then. Could you please share your schematic so that I can review it?

Did you get a chance to check the documentation on the events that cause shutdown as mentioned on my previous post?

Also, do you have bq76PL455A EVMs that you can use to check if you also see the issue with the EVMs?

To avoid confusions I'll go ahead and close the other thread we have on this same issue if that is ok with you. That way we can have all of the information needed and questions on a single thread.

Best regards,
Leslie

Hello Leslie,

I shall share schematics with you in the below attachment. Please review it.

I checked out the documentation on the events that cause shutdown. Shutdown problem seems to be solved now.

We have only one EVM of bq76pl455a which we tested and works well.

You can close other threads. We shall continue with this thread.

8371.SCH.rar

Hi Ritul,

Thank you for the schematic. Let me review it.

You mentioned the shutdown problem seems to be solved. Does this mean the top device stays awake now? What was the issue?

Below is my answer fro the other email thread:

On your scope plot, can you please indicate what each signal is of the 3 signals plotted? Seems like no data is being sent. Did you capture this after a read or write to stack device? You should see data (voltage levels toggling high and low as data is being transmitted). Can you please capture the plot when sending or reading from the top device?

Regarding the error you saw in the GUI, what happened is that when you read from the top device, the PC is waiting for a response from that device and it never received it so you get a timeout error.

Regards,
Leslie