TPS65988: DISC command returns "!CMD"

Cory Van Beek

Part Number: TPS65988

Hello TI Support,

I'm trying to send a DISC command to an attached port on a TPS65988. However, when I send it, the command register gets set to "!CMD" (unrecognized command). I confirmed that my port is in "APP " mode when I send the command.

It looks like I'm not the first person to observe this behavior. Looking at this post, it appears that TI may have a fix, although it wasn't posted on the discussion. Would it be possible to publish this information?

Best regards,

Cory

over 3 years ago

0 Deepak Rozario over 3 years ago

TI__Expert 3190 points

Hi Cory,

Can you capture the I2C logs when performing the following transaction. This would help us know if its the same issue.

Meanwhile, I will follow up with the respective person.

- Deepak

0 Cory Van Beek over 3 years ago in reply to Deepak Rozario

Prodigy 245 points

Hi Deepak,

Yes, here is a screenshot of the I2C logs:

I2C log

Note that the first port (address 0x27) has a device plugged in. On this port, I first write the data byte (1 for 1 s delay), then the DISC command, and then when I read back the command register, it reads "!CMD".

The second port (address 0x23) does not have a device plugged in, after sending the DISC command, the command register reads 0000 and the output is 0x03 (command rejected). This is expected since there is no device attached to the port.

0 Deepak Rozario over 3 years ago in reply to Cory Van Beek

TI__Expert 3190 points

Cory,

Looks like your procedure is correct. Let me look into this and get back to you.

- Deepak

0 Deepak Rozario over 3 years ago in reply to Deepak Rozario

TI__Expert 3190 points

Hi Cory,

I did the experiment on my setup and I get the same results as you. I am currently waiting on few answers. Apologies for the delay.

- Deepak

0 Cory Van Beek over 3 years ago in reply to Deepak Rozario

Prodigy 245 points

Sounds good, thanks for the update

0 Deepak Rozario over 3 years ago in reply to Cory Van Beek

TI__Expert 3190 points

Hi Cory,
I am not having any luck from my end. Looks like I would need sometime as I would have to reach out to the larger team.
-Deepak

0 Deepak Rozario over 3 years ago in reply to Deepak Rozario

TI__Expert 3190 points

Hi Cory,

There is a solution I would testing in a few hours. Will send you an email with the steps in a few hours.

Regards,

Deepak

0 Deepak Rozario over 3 years ago in reply to Deepak Rozario

TI__Expert 3190 points

Solution provided over mail:

The reason you are unable to perform the DISC command is because there is a lock. So it requires a passcode to be sent with the command.
DISC will fail unless you first send 'LOCK' with the HI unlock password (set in App Config, default is CST1)

Could you please try the following:

Data Register 0x9 : write command CST1 (in hex). Perform a write to the PD controller.
Data Register 0x8: Write LOCK 4CC Command.
Data Register 0x8: Write DISC.

Hope this helps. With respect to LOCK command, you can look up the technical reference manual.

- Deepak

0 Cory Van Beek over 3 years ago in reply to Deepak Rozario

Prodigy 245 points

Hi Deepak,

Apologies, it looks like I missed your DM. I should be able to try this out next week at some point.

Thanks again for looking into this.

Best regards,

Cory

0 Deepak Rozario over 3 years ago in reply to Cory Van Beek

TI__Expert 3190 points

No worries Cory.

Regards,

Deepak

Interface

Interface forum

TPS65988: DISC command returns "!CMD"