Toshiba Satellite A300 Maintenance Manual - Page 93

2 Troubleshooting Procedures Code Beeps POST Routine Description 14h Initialize keyboard controller 16h 1-2-2-3 BIOS ROM checksum 17h Initialize cache before memory autosize 18h 8254 timer initialization 1Ah 8237 DMA controller initialization 1Ch Reset Programmable Interrupt Controller 20h 1-3-1-1 Test DRAM refresh 22h 1-3-1-3 Test 8742 Keyboard Controller 24h Set ES segment register to 4 GB 26h Enable A20 line 28h Autosize DRAM 29h Initialize POST Memory Manager 2Ah Clear 512 KB base RAM 2Ch 1-3-4-1 RAM failure on address line xxxx* 2Eh 1-3-4-3 RAM failure on data bits xxxx* of low byte of memory bus 2Fh Enable cache before system BIOS shadow 30h 1-4-1-1 RAM failure on data bits xxxx* of high byte of memory bus 32h Test CPU bus-clock frequency 33h Initialize Phoenix Dispatch Manager 36h Warm start shut down 38h Shadow system BIOS ROM 3Ah Autosize cache 3Ch Advanced configuration of chipset registers 3Dh Load alternate registers with CMOS values 42h Initialize interrupt vectors 45h POST device initialization 46h 2-1-2-3 Check ROM copyright notice 48h Check video configuration against CMOS 49h Initialize PCI bus and devices 4Ah Initialize all video adapters in system 4Bh QuietBoot start (optional) 4Ch Shadow video BIOS ROM 4Eh Display BIOS copyright notice 50h Display CPU type and speed 51h Initialize EISA board 52h Test keyboard 54h Set key click if enabled 58h 2-2-3-1 Test for unexpected interrupts 59h Initialize POST display service 5Ah Display prompt "Press F2 to enter SETUP" 5Bh Disable CPU cache 5Ch Test RAM between 512 and 640 KB 60h Test extended memory 62h Test extended memory address lines 64h Jump to UserPatch1 Satellite A300 Maintenance Manual (960-Q08) 17