BQ76PL536A: SPI not responding

Peter Hunt

Part Number: BQ76PL536A
Other Parts Discussed in Thread: BQ76PL536

Hi,

I have an issue with the bq76pl536 cell monitors in that it is not responding to any SPI commands.

I can see the SPI signals reaching the correct pins but the data out line just remains high. I haven't programmed the OTP registers on the device and was wondering if that might be the issue?

This is on a custom made board but the setup is identical to the evaluation board.

Any ideas as to why it's not responding?

Thanks in advance,

Peter

over 8 years ago

0 Roger Hwang over 8 years ago

TI__Genius 10785 points

OTP has nothing to do with communication.
have you address the device?
YOu have to program the device 1st.

Is HSEL connect to GND?

Are you using your own uC or TI GUI?

0 Peter Hunt over 8 years ago in reply to Roger Hwang

Prodigy 130 points

HSEL is grounded and i'm currently using the TI EVM GUI.

The addressing is the thing it's currently failing to do

How exactly is the device programmed as the programming board seems to no longer be made?

If i turn off the CRC checking and the gui continuously writes i can see something appear on the data output line as seen below if that helps?

0 Roger Hwang over 8 years ago in reply to Peter Hunt

TI__Genius 10785 points

Did you install the USB driver as?

0 Peter Hunt over 8 years ago in reply to Roger Hwang

Prodigy 130 points

I'm fairly sure the gui works correctly as i've used it with the EVM board and it was fine. I can also observe the data output from the gui at the pins of the device and see it's all working as expected. For some reason it's just struggling to respond

0 Peter Hunt over 8 years ago in reply to Roger Hwang

Prodigy 130 points

One more thing, i'm powereing two isolation modules directly from the REG50 output. From the isolation datasheet the supply current may be exceeding the current limit of the REG50 output. The voltage is still sitting happily at 5V but is it possible that this would have an affect on the control logic?

0 Roger Hwang over 8 years ago in reply to Peter Hunt

TI__Genius 10785 points

I need to see your schematic...

REG50 is not a good LDO to use.
It's okay as long as it doesn't exceed but remember, REG50 shuts down in sleepmode.
It means that you can never put IC to sleepmode. Not a good choice.

0 Peter Hunt over 8 years ago in reply to Roger Hwang

Prodigy 130 points

I've now discovered the issue. It turns out the schematic wasn't as identical to the EVM as i thought and i forgot to tie the south comm lines of the bottom chip to ground. I connected all these to ground and it started working.

Thanks for pointing that out about REG50. I hadn't considered REG50 turning off in sleep mode. I will have to ensure that the chip is never put into sleep mode since REG50 is used as an enable line for the power supplied to the whole system in our design (to avoid over discharge of the pack in undervoltage mode).

Thanks,
Peter

0 Roger Hwang over 8 years ago in reply to Peter Hunt

TI__Genius 10785 points

Yes, that will cause the communication issue for sure.

Power management

Power management forum

BQ76PL536A: SPI not responding