CYPD3177: Device mode returning 0x95, other registers 0

[pleasework]

Hi,

I am trying to use the CYPD3177 over I2C to control a USB-PD SRC. After connecting a USB-PD 100W supply:

- FLIP signal rises from 0 to 3v3

- USBPD Bus rises from 0 to 5V

- Activity on CC pins (assuming successful negotiation)

The hardware seems happy. But i am getting strange results from the I2C reads:

DEVICE_MODE returns 0x95 instead of quoted "always returns 0x92". I've attached the bus transaction.

Other registers such as status, silicon ID return 0 over successful I2C reads. It's like my IC has been disabled for I2C mode.

Any ideas?

Evan

[Abhilash_P · Accepted solution]

Hi,

       The DEVICE_MODE register description in the HPI spec is  wrong.

Actually every CYPD3177 chip returns 0x95.  This issue in the BCR HPI spec will be updated in the future revisions. 

Regards,

Abhilash P