HP Dc7700 HP Compaq dx7300 and dc7700 Business PC Technical Reference Guide, 1 - Page 151

SMBIOS, 8.7 USB Legacy Support

Page 151 highlights

BIOS ROM 8.6 SMBIOS In support of the DMI specification the PnP functions 50h and 51h are used to retrieve the SMBIOS data. Function 50h retrieves the number of structures, size of the largest structure, and SMBIOS version. Function 51h retrieves a specific structure. This system supports SMBIOS version 2.4 and the following structure types: Type 0 1 2 3 4 7 8 9 13 15 16 17 19 20 31 32 Data BIOS Information System Information Base board information System Enclosure or Chassis Processor Information Cache Information Port Connector Information System Slots BIOS Language Information System Event Log Information Physical Memory Array Memory Devices Memory Array Mapped Addresses Memory Device Mapped Addresses Boot Integrity Service Entry Point System Boot Information ✎ System information on these systems is handled exclusively through the SMBIOS. 8.7 USB Legacy Support The BIOS ROM checks the USB port, during POST, for the presence of a USB keyboard. This allows a system with only a USB keyboard to be used during ROM-based setup and also on a system with an OS that does not include a USB driver. On such a system a keystroke will generate an SMI and the SMI handler will retrieve the data from the device and convert it to PS/2 data. The data will be passed to the keyboard controller and processed as in the PS/2 interface. Changing the delay and/or typematic rate of a USB keyboard though BIOS function INT 16 is not supported. Technical Reference Guide www.hp.com 8-17

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Technical Reference Guide
www.hp.com
8-17
BIOS ROM
8.6 SMBIOS
In support of the DMI specification the PnP functions 50h and 51h are used to retrieve the
SMBIOS data. Function 50h retrieves the number of structures, size of the largest structure, and
SMBIOS version. Function 51h retrieves a specific structure. This system supports SMBIOS
version 2.4 and the following structure types:
System information on these systems is handled exclusively through the SMBIOS.
8.7 USB Legacy Support
The BIOS ROM checks the USB port, during POST, for the presence of a USB keyboard.
This
allows a system with only a USB keyboard to be used during ROM-based setup and also on a
system with an OS that does not include a USB driver.
On such a system a keystroke will generate an SMI and the SMI handler will retrieve the data
from the device and convert it to PS/2 data. The data will be passed to the keyboard controller
and processed as in the PS/2 interface. Changing the delay and/or typematic rate of a USB
keyboard though BIOS function INT 16 is not supported.
Type
Data
0
BIOS Information
1
System Information
2
Base board information
3
System Enclosure or Chassis
4
Processor Information
7
Cache Information
8
Port Connector Information
9
System Slots
13
BIOS Language Information
15
System Event Log Information
16
Physical Memory Array
17
Memory Devices
19
Memory Array Mapped Addresses
20
Memory Device Mapped Addresses
31
Boot Integrity Service Entry Point
32
System Boot Information