Integrated USB-C Usage

SMLink1 is used to communicate with USB-C* PD Controller on the platform to configure different modes such as USB, DP, Thunderbolt etc. When used for Integrated USB-C purposes, a soft strap must be set to indicate that integrated USB-C ports from CPU are being used.

SMLINK1 uses master mode and gets an alert signal from PMCALERT#.

Based on capabilities of different PD Controllers, re-timers needed for USB-C connector on the platform may need to be controlled by SoC also. In these cases, both PD Controller and Re-timers will be connected to SMLink1. SMLink1 is used for all USB-C connectors on the platform.

U-SKU supports four integrated USB-C ports and Y-SKU supports three integrated USB-C ports. Due to this, there could be maximum of four PD Controller and four re-timers. This translates to maximum of eight devices on the SMLINK1 bus for a platform.

USB-C connectors are present on edges of systems and could also be on opposite ends, so (SMLink1, PMCAlert) could be routed to long distance on the motherboard provided total bus capacitance specification is met.

USB-C Re-timer control (like Firmware Load, USB-C configuration) handling depends on the number of I²C ports available on the PD controller.

If the PD controller has two I²C ports then PCH PMC will handle the Re-timer and PD controller, but if the PD controller has three or more I²C ports then PCH PMC will handle only PD controller. Re-timers can be handled by PD controller.

SMLink1 should be run at 400 kHz when used for USB-C purposes.