BQ76PL455EVM: Differential Comms not working

Vikram Jain

Part Number: BQ76PL455EVM

Hi All,

I want to use two BQ EVM's for series communication (i only want to test the software for communication working) do i need to get any hardware changes on top BQ EVM in stack to get both of them working as daisy chain and communicate ?

I have not even series'd the cell connections from bottom board to top board. Do i need to do any changes also ?

All i have done now is connected the J5 of bottom device to J4 of top device for daisy chain communication and 2 nobs on SW2 is set to direct towards diff side.

Am i missing something ?

over 7 years ago

0 David Wiest Jr over 7 years ago

TI__Genius 11480 points

Hi Vikram,

Please see my response in your previous thread. We can probably continue that thread, since this is related to the original issue.

0 Vikram Jain over 7 years ago in reply to David Wiest Jr

Intellectual 485 points

Cant see the response in that thread, but got email notification so got your reply, but i have cross checked all the diff comms connections and they seems to be okay ? What else could be wrong ? any hardware issues that i can look for ?

0 Vikram Jain over 7 years ago in reply to Vikram Jain

Intellectual 485 points

Hi David Wiest Jr ,

My differential communication doesn't seems to be working the COMMH and COMML signals when i measure it with the scope to falling down to 4-4.1V.

The issue is very odd it does not immediately fail but it works for couple of secs and then get a corrupted packet. When i request for 16VSENSE meas the rx len is 35 but when i get the packet and check the length by reading the 1st byte of rx packet the length there is 47 and fails on CRC since the data is corrupted

I am using CAT65 cable and the length is 1/2 meters and UART baud is 1mbit. Can you please help me where shall i debug this issue ?

Kind Regards

Vikram Jain

0 Vikram Jain over 7 years ago in reply to Vikram Jain

Intellectual 485 points

Hi David Wiest Jr waiting for you response ? anybody else can also reply me please. This is going into production and we are aiming for nearly 100000 pieces, if this does not work reliably we switch to LTC part so please help.

0 David Wiest Jr over 7 years ago in reply to Vikram Jain

TI__Genius 11480 points

Hi Vikram,

I received your email, and will respond to you there. I apologize for the delay.

0 Vikram Jain over 7 years ago in reply to David Wiest Jr

Intellectual 485 points

Hi David,

Thank you. awaiting your response please reply ASAP.

Kind Regards

Vikram Jain

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BQ76PL455EVM: Differential Comms not working