TPS65982: How to see that both Power Delivery partner devices don't negotiate not finding a common PDO?

Yevhen Horbenko

Part Number: TPS65982

Hi guys,

I appreciate your help.

In my software I'm changing currents values in 0x32 TX Source Capabilities Register and performing SSrC to renegotiate the contract.

Let's assume that after editing there's no appropriate PDO for the partner device.

1) How could I detect this fact?

2) Would 0x34 Active Contract PDO Register be equal to zero?

3) Would 0x3F Power Status Register "PowerConnection" field be equal to "No connection (rest of bits in this register are not valid)"?

4) Would 0x1A Status Register "PlugPresent" field be equal to "No plug present"?

over 5 years ago

0 Adam Mc Gaffin over 5 years ago

TI__Mastermind 29995 points

Hello Yevhen,

There will always be at least a 5 V contract that can be negotiated between the two device if they are compliant.

0 Yevhen Horbenko over 5 years ago in reply to Adam Mc Gaffin

Intellectual 510 points

Ok, but what's about a case when SNK device wants 5V with 3A operational (and min) current and SRC device can supply maximum only 5V-2A?

What the behavior would be in registers from my question?

0 Adam Mc Gaffin over 5 years ago in reply to Yevhen Horbenko

TI__Mastermind 29995 points

They will still negotiate an implicit Type-C contract via the pullup (Rp) and pulldown (Rd) resistors connected to the CC channels. The PD controller will still show a device connection

0 Yevhen Horbenko over 5 years ago in reply to Adam Mc Gaffin

Intellectual 510 points

So would I read 0x34 Active Contract PDO Register as zeroes in this case?

0 Adam Mc Gaffin over 5 years ago in reply to Yevhen Horbenko

TI__Mastermind 29995 points

Potentially. But the two devices would most likely still negotiated a contract with a 5 V PDO, so you would read that in register 0x34

Interface

Interface forum

TPS65982: How to see that both Power Delivery partner devices don't negotiate not finding a common PDO?