What would be default charging behavior if both CC1/2 pulled high?

[VRRV]

Hi everyone,
I'm thinking about implementation of SWD-over-USB with proper DAM (both CC1/CC2 pulled high). It is not totally clear to me what would be default nPM's behavior in this case - does it resort to 100mA charging only/no charging at all or, because it needs either of CC1/CC2 to be pulled high, it will behave normally and charge battery as per configuration?

Sorry for lame question, doesn't have DK handy to test it and need answer ASAP.

Thank you All!

[Priyanka]

Hi,

The CC1 and CC2 are basically used to detect the USB connection.

And for this, you need one CC pulled down and the other pulled up. And this voltage difference (determined using comparators) over the Rd (pull-down resistor) is what determines the USB detection.

And in case you are not using a USB, then you can either leave both CCs floating or grounded.

But keeping both CCs high is not the recommended state, as this will not give a voltage difference which we can use to measure the required USB detection.

Hence, the PMIC will not see a valid voltage state for USB detection, and since the USB detection was not done,  the VBUS limit should stay at 100 mA (as long as the valid voltage conditions are met for VBUS).

-Priyanka

[VRRV]

So, 100mA... thank you! )
USB specification define DAM (Debug Accessory Mode), it requires both CC to be pulled high... that's why I am asking.

[Priyanka]

Yes, in Zephyr I see there is the DAM in the USB specs, i.e., if both CC lines are high, this is a DAM state and if just one is high, then normal USB detection.

But this DAM mode is not there in the nPM series as they are just PMICs which are used to charge and manage power.

-Priyanka

[VRRV]

Got it, thank you!