BQ76PL536A: No response on SPI communication line

Dhaval Waghulde

Part Number: BQ76PL536A

BE76PL536A EVM: I am able to communicate to EVM using Arduino and using F28069 launchpad. I am able to read all cells voltages and other register values. Image below which shows the oscilloscope capture of communication, data is correctly decoded by oscilloscope as well as received correctly at SPI receive registers.

CH1: MISO

CH2: SCLK

CH3: MOSI

CH4: SS

Custom board: I am trying to communicate with BQ76PL536A IC on a custom board designed be me. I tried using both Arduino and F28069 launch pad with same code but cant get a response from IC. I dont think software is an issue because I am using same code. Please see images below. It can be seen that MISO line stays high when slave select is low.

CH1: MISO

CH2: SCLK

CH3: MOSI

CH4: SS

Here my voltage measurements on the custom board

Bat1 and Bat2: Tried 12V to 24V (using a DC power supply)

LDO1: 4.92V

LDO2:4.92V

LDOA: 5.63V

REG50: 6.09V

Vref:2.49V

I tried 2 boards(same design) and tried replacing IC on one board. I still get same voltages as above and same MISO waveform as attached.

Why am I not getting a response on MISO line? Any suggestions? Let me know if I can share any more information.

over 5 years ago

0 Taylor Vogt over 5 years ago

TI__Genius 17370 points

Hi Dhaval,

If the code is proven to work on EVM, then it is best to compare your custom hardware design to our EVM reference schematic to see any potential differences. Is there anything unique from the reference design that we could look into?

Taylor

0 Dhaval Waghulde over 5 years ago in reply to Taylor Vogt

Prodigy 40 points

Thanks for you reply.

Have you ever seen VREG50 = 6V? Datasheet mentions range of 4.9 to 5.1, so I am not able to understand why i see 6V.

While using EVM or custom board, I am not connecting cells(battery), just using DC power supply between CELL6P (it is shorted to VBAT) and ground.

Here are some differences. While using Arduino with custom board, I don't have digital isolator as used in EVM. LDOD1 is not connected to LDOD2 in my board.

Here is my schematic below. Let me know if you find anything wrong in it.

0 Dhaval Waghulde over 5 years ago in reply to Dhaval Waghulde

Prodigy 40 points

REG50 capacitor was not soldered, soldered it now. Also connected LDOD1 and LDOD2. Now I get

LDO1: 4.92V

LDO2: 4.92V

LDOA: 5V

REG50: 5V

Vref: 2.49V

Now the voltages look better but I still getting same waveform for MISO. Any suggestions?

0 Leslie Marquez over 5 years ago in reply to Dhaval Waghulde

TI__Genius 9401 points

Hi Dhaval,

Please double check that the component values (e.g. caps, resistors) are the ones recommended in the device datasheet? The schematic you shared does not have component values.

Regards,

Leslie

0 Leslie Marquez over 5 years ago in reply to Leslie Marquez

TI__Genius 9401 points

Hi Dhaval,

Do you still need help with this issue?

Regards,

Leslie

0 Dhaval Waghulde over 5 years ago in reply to Leslie Marquez

Prodigy 40 points

Hi Leslie,

Thanks for asking. I still have the same issue. I am not sure where I am going wrong. I think I have all component values same as recommended in datasheet/EVM. If you have any suggestions then let me know. I will keep trying.

Thanks,

Dhaval

0 Leslie Marquez over 5 years ago in reply to Dhaval Waghulde

TI__Genius 9401 points

Hi Dhaval,

I mentioned earlier that the schematic you shared does not have any component values displayed. Can you please provide this so we can review the schematic?

Regards,

Leslie

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BQ76PL536A: No response on SPI communication line