Toshiba Portege R100 Maintenance Manual - Page 57

2.4 System board Troubleshooting 2 Troubleshooting D port status F000h F001h F002h F005h F006H F007h F008h F009h Table 2-3 D port status (1/6) Inspection items Start CHECK SUM CHECK Initializing a KBC (1) Checking F12 key-in Checking whether BIOS rewrite is requested Checking BIOS signature Rewriting BIOS details Clearing a software reset bit Enabling address line A20 Initializing special registers and Intel chipset Initializing the CH0 of a PIT Initializing flags determining whether BIOS is rewritten CHECK SUM CHECK Switching to protected mode Examining the checksum of Boot Block Examining the checksum of other data in a flash memory Checking if EC/KBC firmware is to be rewritten Initializing a KBC Sending command bytes Sending scan enable command Checking F12 key-in Initializing a security controller Checking whether BIOS rewrite is requested Checking BIOS signature Initializing HW Initializing GPIO I/O space Enabling BIOS writing Serial interrupt control Disabling BIOS write protection Enabling SMBus I/O space Enabling SMBus access Configuring DRAM Enabling L1 cache memory Clearing memory Disabling cache Initializing special registers Changing ROM BIOS to RAM BIOS Storing key scan code Setting up TASK_1ms_TSC Displaying message on navipanel (EC/KBC UPDATE, BIOS UPDATA/DAMAGED) PORTEGE R100 Maintenance Manual (960-440) 2-21