2 Troubleshooting Procedures 2.4 System Board Troubleshooting Table 2-5 Printer port LED boot mode status (1/7) LED Status Test item Message
Clearance of software reset bit
Permission of A20 line
Start
Initialization for special register and Intel chip set
PIT CH0 initialization (for HOLD_ON)
BIOS rewrite flag initialization
Checksum check (FEF00000h-FEFF7FFFh)
Transition to protected mode
Boot block checksum (HLT when checksum error
occurred.)
B0h Flash ROM check
Checksum check except boot block
B1h EC/KBC rewrite check Transition to BIOS rewriting when required
B2h Start initializing the SC (HLT when Initialization for SC error occurred) B3H
(HLT when processing the SC can not be continued by
the HW failure) B4H
Executing initialization of KBC
sequence transmission of KB enable command
Key check at Boot Block
B5h Enabling CPU cache
B6h BIOS signature check
BIOS rewrite request check Checksum error except boot block
(When key rewriting is requested, go to BIOS rewrite
process)
System BIOS rewrite transition to
IRT
Rewriting BIOS
Setting of base for Power Management I/O Space
Permission of BIOS writing
Serial interrupt control
Releasing BIOS rewrite protection
Enabling SM Bus I/O space
Enabling SM Bus access
Opening work I/O for SDRAM initialization
H/W initialization
Setting FDC port
Initialization of PIT channel 1
(Setting refresh interval to 30ms)
Initialization of PIT, DMAC, PIC
B7h
Prohibition of cache