SECTION 7
System Information
PEN*KEY
R
6200/6300 Hand-Held Computer Programmer’s Reference Guide 7-15
Table 7Ć7 (Continued)
I/O Address and Devices
I/O Address Device
390 ć 29F
Reserved for PC Card general use
3A0 ć 3AF
Reserved (PC Card/SDLC)
3B0 ć 3BF
Reserved (MDA/EGA/VGA)
3B0 ć 3DF
VGA/CGA
3E0 ć 3E1
PC Card controller
3E8 ć 3EF
Reserved For PC Card serial port 3
3F6 ć 3F7
Reserved for PC Card (primary ATA/IDE disk controller)
3F8 ć 3FF
COM 1
BIOS/CMOS System Variables
ROM BIOS is system software at the lowest layer of a PC operating
environment. ROM BIOS provides a hardware abstraction level in a system so
that higher levels of software need not be concerned with certain hardware
details. Occasionally, it is helpful to examine the ROM BIOS or at least look at
the data that it uses to get its job done. The following are lists of data areas on
which the ROM BIOS operates.
ROM BIOS Data Area
A PCĆcompatible ROM BIOS uses system variables that are stored, starting at
location 40:0h. This address starts the first block of data immediately following
the interrupt vector table. A
de facto
industry standard defines most of the
variables on which a ROM BIOS must operate. In the following table, the
entries that are unique to the NORAND BIOS are
italicized and bold
. The
remaining entries are defined in accordance with the industry standard.
Table 7Ć8
BIOS Data in System RAM
Addr Size
Description
40:00 4 words
I/O address of up to 4 ASYNC communications adapters (COM1ćCOM4)
40:08 3 words
Reserved: I/O address, up to 3 printer adapters (LPT1 LPT3)
40:0E Word
Segment address of extended BIOS Data Area
40:10 Word
Equipment status word (Returned by interrupt 11h)
40:12 Byte
Reserved: POST status
40:13 Word
Conventional memory size in kilobytes (returned by INT12h)
40:15 Word
Pass/Fail indicators for RAM POST test
40:17 Word
Keyboard shift flags
40:19 Byte
AltĆkeypad accumulator
40:1A Word
Pointer to next keycode in keyboard buffer
40:1C Word
Pointer to next available location to save keycode in keyboard buffer
40:1E 16 words Circular keyboard buffer
40:3E Byte
Reserved: disk recalibrate status
40:3F Byte
Reserved: disk motor status
40:40 Byte
Reserved: disk master timeout control
40:41 Byte
Disk status return codeĊstatus of last RAM card access
40:42 7 bytes
Reserved: disk controller status bytes
40:49 Byte
Video mode setting
7. System Information
