Intel® Core™ Ultra Series 3 Processors I/O Registers
| ID | Date | Version | Classification |
|---|---|---|---|
| 872352 | 04/14/2026 | 001 | Public |
Traffic Class Assignments (TCA) – Offset 1c10
This register controls the traffic class assignments for the SOC.
There are reserved TC in the SOC that cannot be used, hardcoded through the parameter TCRSVD.
If the value programmed into the TCSM or TC1 fields matches the reserved TC values, then hardware should treat the corresponding register field as 0h, i.e. the corresponding VC is treated as disabled in SOC and should not be used.
| Bit Range | Default | Access | Field Name and Description |
|---|---|---|---|
| 31:16 | 0h | RO | Reserved (Preserved) (RSVD31) SW must preserve the original value when writing. |
| 15:12 | 8h | RW | VCusb Traffic Class (TCUSB) When the IOSF Primary interface is enabled to use VCusb, they must use this traffic class. Parameter TCUSBCHM will decide which IOSF Primary interface channel VCusb is being mapped to. |
| 11:4 | 0h | RO | Reserved |
| 3:0 | 0h | RO | VC0 Traffic Class (TC0) This is the mandatory TC for all PCI Devices (host root space) to use to communicate with host CPU. |