Intel® Core™ Ultra 200S and 200HX Series Processors SOC I/O Registers
| ID | Date | Version | Classification |
|---|---|---|---|
| 834819 | 01/29/2025 | 001 | Public |
Version Register (VS) – Offset 1
Each I/O APIC contains a hardwired Version Register that identifies different implementation of APIC and their versions. The maximum redirection entry information is also in this register to let software know how many interrupt are supported by this APIC.
| Bit Range | Default | Access | Field Name and Description |
|---|---|---|---|
| 31:24 | 0h | RO | Reserved (RSVD) Reserved |
| 23:16 | 77h | RW/O | Maximum Redirection Entries (MRE) This is the entry number (0 being the lowest entry) of the highest entry in the redirection table. This field is defaulted to 17h to indicate 24 interrupts. This field is Read-Write-Once. BIOS must write to this field after PLTRST# to lockdown the value. This allows BIOS to utilize some of the entries for its own purpose and thus advertising fewer IOxAPIC Redirection Entries to OS. |
| 15 | 0h | RO | Pin Assertion Register Supported (PRQ) Indicate that the IOxAPIC does not implement the Pin Assertion Register. |
| 14:8 | 0h | RO | Reserved (RSVD_1) Reserved |
| 7:0 | 20h | RO | Version field (VS) Identifies the implementation version as IOxAPIC. |