Specifications

130 AMD Geode™ GeodeROM Functional Specification
System Services
32087C
12.1.10 Function BEh - AMD OEM Functions
The AMD OEM functions can be broadly divided into the following categories:
• ACCESS.bus Access Functions Specific to Geode™ Devices:
— GeodeROM provides the following functions to access ACCESS.bus devices installed in the system. These can be
used in platform-specific modules or when writing tools and utilities.
— ACCESS.bus access functions specific to Geode devices, INT 15h, Function BEh:
– Subfunction 00h: Read ACCESS.bus Byte
– Subfunction 01h: Write ACCESS.bus Byte
– Subfunction 02h: Write ACCESS.bus Block
• NVRAM Access Functions Specific to Geode Devices:
— GeodeROM provides the following functions (specific to Geode devices) to access the installed NVRAM devices in
the system. Information is accessed through a token rather than an absolute address. This eliminates the necessity of
knowing specific addresses, and allows for future reorganization of the NVRAM map.
— Note that although these BIOS calls are present and functional, they are intended for forward compatibility. Currently,
GeodeROM (POST) does not use information found in NVRAM. All initialization values are specified using the config-
urator.
— NVRAM access functions specific to Geode devices, INT 15h, Function BEh:
– Subfunction 03h: Read NVRAM Data
– Subfunction 04h: Write NVRAM Data
– Subfunction 05h: Get Default NVRAM Value
– Subfunction 06h: Get NVRAM Checksum
– Subfunction 07h: Set NVRAM Checksum
– Subfunction 08h: Reset NVRAM Default
– Subfunction 09h: Get NVRAM Table Address
• Access Functions to a Specific Geode Platform and/or other AMD Device:
— GeodeROM provides the following functions for Geode specific platforms and other AMD devices installed in the
system.
— Access functions to a specific Geode platform and/or other AMD device:
– Subfunction 0Ah: ACCESS.bus Block Read
– Subfunction 20h: Get SCxxxx External Clock Speed
– Subfunction 21h: Get SCxxxx Device Type
– Subfunction 31h: SCxxxx Read ACCESS.bus Device
– Subfunction 32h: SCxxxx Write ACCESS.bus Device
– Subfunction 35h: Owl Board Specific Feature Access
– Subfunction A0h: Wait for Key Timeout
– Subfunction A1h: Get ROM Data
– Subfunction A2h: CPU Memory Register Read INT
– Subfunction A3h: CPU Memory Register Write INT
– Subfunction A4h: Get CPU Speed
– Subfunction A5h: Check CMOS
– Subfunction A6h: CMOS Check Power
– Subfunction A7h: Get PCI Speed
– Subfunction A8h: Set Warning
– Subfunction A9h: Read Companion Chip DWORD
– Subfunction AAh: CPU Register Read
– Subfunction ABh: CPU Register Write
– Subfunction ACh: Eat Key
– Subfunction B0h: Get Shadow
– Subfunction B1h: Set Shadow
– Subfunction F0h-FFh: User Defined Interrupts