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I2C.md

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I2C addresses in this document include the R/W bit.

USB Hub @ 0x5A

As I2C pullups are present on this board, the hub will wait for configuration before becoming active. The upstream superspeed mux should be set first.

Type C Port Controllers (TCPC)

  • Register information is in PTN5110_AN2137.pdf rather than the data sheet.
  • The FRS pin is used as a GPIO to control the superspeed mux. See EXT_GPIO_CONFIG/CONTROL registers.
  • The interrupt pin is not wired due to lack of pins on the AVR. The TCPCs will need to be periodically polled.
  • All support full USB PD communication, but this does not have to be used
  • Can source VCONN for active cables, electronic markers

Upstream @ 0xA2

  • The CC_STATUS reigster can be read to determine connector orientation and available power.
  • A PD contract may allow more power than indicated in CC_STATUS, for example, a device that can source 2 A would report 1.5 A via CC_STATUS.
  • PTN5110DHQ which defaults to acting as a power sink.
  • Defaults should be OK except for GPIO setup on FRS.

Downstream C Left @ 0xA4, Right @ 0xA0

  • PTN5110THQ which defaults to acting as a power source
  • The AVR will need to poll for cable connects and disconnects. tVbusOFF in the USB C spec is 650 ms which sets the maximum polling interval.
  • The SRC pin is used on the downstream ports to enable sourcing power. It may be required to switch the SRC pin to a GPIO so that sourcing power is only enabled after the superspeed mux is set properly.
  • It's probably best to only offer default power.