BQ40Z50-R2: Issues in reading SMBUS data

Hi Ashutosh,

The PEC should be disabled if HPE is cleared, has the device been reset after the change has been made?

Also, can you please share a scope shot of what's being seen?

Regards,

Anthony

Hello Anthony,

PEC is disabled, again ensured by clearing HPE and resetting the device.

I have gathered initial data (while they start communicating) of 2 different guages with the same master.(LINK Below)

New Guage (BQ40z50-R2) and Old Guage (BQ34z950).

I'm unable to get the SMbus data with a new guage whereas old guage is working fine. Please analyze the data and suggest the possible solution for the same.

https://emselectronica-my.sharepoint.com/:u:/g/personal/ashutosh_k_emselectronica_onmicrosoft_com/EaDFjUP-Eq5Eg5ERHr0SxYUBULLy64gW8u3pukYRoojEUQ?e=ymX09Z

                                 BQ40z50-R2                                                                                                                                                BQ34z950

Best Regards,

Ashutosh K.

Hi Ashutosh,

Thank you for sending this information. In the image of the bq40z50, it seems like there is a command being sent very shortly prior. Can you please confirm the time between these commands?

Can you please also try enabling the FLASH_BUSY_WAIT bit in the SBS Configuration Register of the bq40z50 to see if there is any difference at this time as well?

Regards,

Anthony

Hello Anthony,

FLASH_BUSY_WAIT bit is already enabled in SBS Configuration Register of BQ40z50-R2.

The timing conditions between two gauges old and new one are also similar.

The issues seems partially solved. On the display of our product the battery parameters can be seen but there is a fluctuation in the values during charging mode. Also in discharging there is no communication i.e battery parameter values are not displayed or updated.

I have calculated min and max values of the pullup resistor which comes as 944 ohms and 3.77 kohms. I tried multiple values of the pull up resistor at the controller side but the issue hasn't resolved. Is there anything I'm missing.

Regards,

Ashutosh K

Hi Ashutosh,

What is the Valid Update Voltage at this time? There should be no difference in the communication between rest, charge, and discharge, can you please confirm that the communication waveforms meet the thresholds below? During discharge, is there any chance the gauge is going into shutdown?

Regards,

Anthony

Hello Anthony,

I confirmed the communication waveforms meet the thresholds. The problem is still there during discharging cycle.

One more problem we are facing is as below.

We are using BQ40Z50 SMBUS to read parameters like voltage, current and percentage, all are reading OK.

We want to read "CCC Current threshold" (0x4A76), while reading block using 0x44 command, we are not getting proper values for CCC current threshold.

What is SMBUS read block sequence for CCC Current threshold, and any access need to set for reading parameter CCC current threshold.

We are using following write and read sequence over SMBUS as:

0x16  0x44  0x02 0x60  0x4A => Write ( As CCC current threshold stored in flash block address 0x4A60)

0x16  0x44  0x17 ..................=> Read

Regards,

Ashutosh K

Hi Ashutosh,

Ashutosh Kedare said:

I confirmed the communication waveforms meet the thresholds. The problem is still there during discharging cycle

Is there any difference in the waveform during the discharge? There should be no difference in the communication whether in charge, discharge, or relax.

Ashutosh Kedare said:

What is SMBUS read block sequence for CCC Current threshold, and any access need to set for reading parameter CCC current threshold.

We are using following write and read sequence over SMBUS as:

0x16  0x44  0x02 0x60  0x4A => Write ( As CCC current threshold stored in flash block address 0x4A60)

0x16  0x44  0x17 ..................=> Read

Below is if I conduct a block write for 0x4A60, I believe the PEC bit is being missed above:

Regards,

Anthony