Specifications

AMD Geode™ GeodeROM Functional Specification 63
Non-Removable Media
32087C
17h BYTE Keyboard status byte (1 of 2):
Bit 7 = INSert key active
Bit 6 = CapsLock key active
Bit 5 = NumLock key active
Bit 4 = Scroll Lock key active
Bit 3 = Either ALT key pressed
Bit 2 = Either CTRL key pressed
Bit 1 = Left Shift key pressed
Bit 0 = Right Shift key pressed
18h BYTE Keyboard Status byte (2 of 2):
Bit 7 = INSert key pressed
Bit 6 = CapsLock key pressed
Bit 5 = NumLock key pressed
Bit 4 = Scroll Lock key pressed
Bit 3 = Pause state is active
Bit 2 = SysReq key pressed
Bit 1 = Left ALT key pressed
Bit 0 = Left CRTL key pressed
19h BYTE Keyboard Alt-<Number> Scratchpad: Used by the BIOS to build a three-digit ALT-nnn ASCII
code.
1Ah WORD Keyboard: Offset of next character in the keyboard buffer that starts at 40:1Eh.
1Ch WORD Keyboard: Offset of next empty location in the keyboard buffer that starts at 40:1Eh.
1Eh 16 WORDs 16 Character keyboard buffer.
3Eh BYTE Diskette recalibrate status:
Bit 7 = Floppy controller IRQ occurred
Bits [6:4] = Unused
Bit 3 = 1 if diskette 3 requires recalibration
Bit 2 = 1 if diskette 2 requires recalibration
Bit 1 = 1 if diskette 1 requires recalibration
Bit 0 = 1 if diskette 0 requires recalibration
3Fh BYTE Diskette drive motor status:
Bit 7 = 0 if current operation is verify or read
Bit 7 = 1 if current operation is format or write
Bit 6 = Unused
Bits [5:4] = Currently selected diskette drive (0-3)
Bit 3 = 1 if diskette 3 motor is on
Bit 2 = 1 if diskette 2 motor is on
Bit 1 = 1 if diskette 1 motor is on
Bit 0 = 1 if diskette 0 motor is on
40h BYTE Number of 18.2 Hz timer ticks until floppy motor is shut off.
41h BYTE Status of last diskette operation (0 = No error):
Bit 7 = 1 if drive not ready
Bit 6 = 1 if a seek error occurred
Bit 5 = 1 if a controller failure occurred
Bits [4:0] = Other error conditions:
01h = Invalid command
02h = Sector address mark not found
03h = Disk write protect error
06h = Change line is active
08h = DMA overrun
09h = Attempt to DMA across 64 KB page boundary
0Ch = Unable to determine media type
0Eh = CRC error during read operation
Table 6-3. Format of the BIOS Data Area (Continued)
Offset Size Description