Usb Legacy Support - Compaq iPAQ 1.0 Technical Reference Manual

The APM BIOS for this system supports APM 1.2 as well as previous versions 1.1 and 1.0. The
APM BIOS functions are listed in Table 8-3.
Table 8-4. APM BIOS Functions (INT15)
AX
5300h
5301h
5302h
5303h
5304h
5305h
5306h
5307h
5308h
5309h
530Ah
530Bh
530Ch
530Dh
530Eh
530Fh
5380h
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.
The system does not support hot-plugging of a USB keyboard, nor is a keyboard attached to a USB
hub supported. A PS/2 keyboard and a USB keyboard can, however, be connected and used
simultaneously.
Table 8-3.
APM BIOS Functions (INT15)
Function
APM Installation Check
APM Connect (Real Mode)
APM Connect (16-bit Protected Mode)
APM Connect (32-bit Protected Mode)
Interface Disconnect
CPU Idle
CPU Busy
Set Power State [1]
Enable/Disable Power Management
Restore Power On Defaults
Get Power Status
Get PM Event
Get Power State
Enable/Disable Device Power Management
APM Driver Version
Engage/Disengage Power Management
OEM (Compaq) Specific APM Function
Compaq iPAQ Series of Desktop Personal Computers
Review Copy - January 2001
Technical Reference Guide
8-17