TMS320F280039C: TMS320F280039C interfacing with BQ79731 using SPI communication.

Rahul Jathar

Prodigy 150 points

Part Number: TMS320F280039C

Hi All,

I am interfacing 39C with BQ79731(current monitoring IC) using SPI communication.

i sent wakeup ping to BQ ASIC now it is in Active state.

Wakeup_Pin();

Delay(5000);

ReadReg(0x00 ,TAPEOUT_REV ,Rx_Frame_u8 ,1,0 , FRMWRT_SGL_R);

issue : I send TAPEOUT_REV command to read data from BQ ASIC but not getting Proper response form BQ.

SPI Master : TMS320F280039C

SPI slave : BQ79731 (current monitoring IC)

over 3 years ago

0 Manoj Santha Mohan over 3 years ago

TI__Guru 55700 points

Rahul,

There are multiple E2E threads on the same issue. I think it is better to get on a call to understand the problem.

Can you send me your email address? I will setup a webex call.

Regards,

Manoj

0 Rahul Jathar over 3 years ago in reply to Manoj Santha Mohan

Prodigy 150 points

Hi Manoj,

Thank you for reply. i am facing this issue since many days.

in my organization we are not allowed to use Webex.

it would be better if we have a call on Microsoft teams so i can explain you my issue properly.

my mail id : rahul.jathar@hella.com . arrange the call as per your convenient time.

please try to schedule meeting as early as possible.

0 Manoj Santha Mohan over 3 years ago in reply to Rahul Jathar

TI__Guru 55700 points

Unfortunately, I don't have access to microsoft teams and I need to check whether TI allows me to use it.

0 Rahul Jathar over 3 years ago in reply to Manoj Santha Mohan

Prodigy 150 points

Hi Manoj,

you can arrange call on webex using above mentioned mail id.

0 Manoj Santha Mohan over 3 years ago in reply to Rahul Jathar

TI__Guru 55700 points

Rahul,

I just looked into BQ79731 datasheet, it doesn't show SPI commands that needs to be used to communicate with it. I'm not sure whether you are already working with someone in BQ79731 team. But, unless we know valid command structure master needs to be transmit to BQ79731. We can't be sure of the data that will be received from it. It would be of great help if you share SPI bus scopeshots using logic analyzer with both BQ79731 and C2000 team. We need to get confirmation from BQ79731 whether we are sending the write SPI commands to it.

Regards,

Manoj

+1 Manoj Santha Mohan over 3 years ago in reply to Manoj Santha Mohan

TI__Guru 55700 points

Root cause of customer problem: BQ79731 SPI mode 0 strobes for data on rising edge and changes data on falling edge. But customer was operating SPI master in strobe for data on falling edge and changes data on rising edge. Customer was confused because SPI mode 0 specified in BQ79731 was different from F280039 SPI mode 0. If customer had taken a closer look into timing diagram in both the datasheet, this problem could have been avoided

+1 Rahul Jathar over 3 years ago in reply to Manoj Santha Mohan

Prodigy 150 points

Thank you Manoj , my issue is resolved..

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TMS320F280039C: TMS320F280039C interfacing with BQ79731 using SPI communication.