Texas Microsystems, Inc. 2003 - 3 Operation; Firmware Operation

3. OPERATION
This section describes the operation o£ the computer_
including a description o£ the BIOS and SETUP £irmware
contained on the B286 CPU.
3.1 Firmware Operation
The B286 board contains approximately 32k o£ £irmware
in two 32K x 8 EPROMS. This £irmware per£orms power-on
computer checks, sets up the computer hardware, and
contains the internal setup routines £or con£iguration.
The computer can be restarted using three methods:
1. Cycle the ON/OFF power switch to the ON position.
2. Reboot the computer - Press and hold the CTRL and
ALT keys and then press the DELETE key.
3. Press the RESET pushbutton - the computer stops
processing activities and reboots. This method is
only recommended as a "last resort" because loss
o£ data can result i£ a program is in process.
The BIOS per£orms internal diagnostics to check the
current con£iguration against the con£iguration
in£ormation recorded in CMOS memory during Setup. 1£
inconsistencies exist, BIOS error messages are
displayed. Some o£ these errors can be quickly
corrected by checking the Setup in£ormation. More
technical errors require the assistance o£ trained TMI
technical personnel. Some o£ the elements tested during
BIOS diagnostics include the £ollowing:
Processor CPU chip
DMA controllers
Floppy disk drive controllers
Hard disk drive controller
Hard disk drive con£iguration
Real time clock chip
Interrupt controller chip
Keyboard
Time-o£-day clock (CMOS RAM)
Video controllers
RAM memory
BIOS ROM (check aum used £or validity)
Although BIOS power-up diagnostics are not
comprehensive, the £ew seconds that the BIOS routine
requires are very e££ective in identi£ying problems.
For in depth diagnostics that are more comprehensive
and require more time, the International Business
Preliminary AT Users Manual
8 11/26/86