Specifications

AMD Geode™ GeodeROM Functional Specification 89
10
Human Interface Device Support 32087C
10.0Human Interface Device Support
This chapter describes GeodeROM’s support for human interface devices (HID), such as keyboards and pointing devices.
GeodeROM provides full support for 101 key PC keyboards. It contains a full implementation of the INT 16h interface as
described in numerous books on the subject of low level PC programming. Additionally, GeodeROM contains an IRQ1 han-
dler and supports INT 15h Function 4Fh (Scan Code Redirect) as a means of enabling TSRs (Terminate, Stay Resident)
and any other software that intercepts keystrokes.
In addition to the standard PS/2 keyboard device, the INT 16h interface transparently supports the Legacy USB Keyboard.
10.1 INT 16h Functions Descriptions
This section lists those INT 16h functions supported in GeodeROM, the parameters that system software supplies to each
INT 16h function and the values that each function returns.
10.1.1 Function 00h - Wait For Character
Description:
Returns after a keystroke occurs, ignoring any non-standard keystroke.
Passed:
Returns:
Related Functions:
INT 16h "Function 10h - Get Extended Key Code" on page 92.
Table 10-1. INT 16h HID Functions
Function Number/Name Page Number
Function 00h - Wait For Character 89
Function 01h - Check For Key Present 90
Function 02h - Get Shift Status 90
Function 03h - Set Keyboard Typematic Rate 91
Function 05h - Insert Key Code In Keyboard Buffer 91
Function 10h - Get Extended Key Code 92
Function 11h - Check For Enhanced Key Code 92
Function 12h - Get Extended Shift Status 93
Parameter Description
AH 00h
Parameter Description
AH Scan code
AL Character