Kontron MSM800BEV - Manual (Page 50)

MSM800BEV / Detailed System Description
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Location Description
2Ah
Byte 5
Bits 7-0 = Sectors Per Track
2Bh
Boot Password
Bit 7
= Enable/Disable Password
0 = Disable Password
1 = Enable Password
Bits 6-0 = Calculated Password
2Ch
SCU Password
Bit 7
= Enable/Disable Password
0 = Disable Password
1 = Enable Password
Bits 6-0 = Calculated Password
2Dh Reserved
2Eh High Byte of Checksum - Locations 10h to 2Dh
2Fh Low Byte of Checksum - Locations 10h to 2Dh
30h Extended RAM (kB) detected by POST - Low Byte
31h Extended RAM (kB) detected by POST - High Byte
32h BCD Value for Century
33h
Base Memory Installed
Bit 7
= Flag for Memory Size
0 = 640kB
1 = 512kB
Bits 6-0 = Reserved
34h
Minor CPU Revision
Differentiates CPUs within a CPU type (i.e., 486SX vs 486 DX, vs 486 DX/2). This is crucial for correctly
determining CPU input clock frequency. During a power-on reset, Reg DL holds minor CPU revision.
35h
Major CPU Revision
Differentiates between different CPUs (i.e., 386, 486, Pentium). This is crucial for correctly determining CPU
input clock frequency. During a power-on reset, Reg DH holds major CPU revision.
36h
Hotkey Usage
Bits 7-6 = Reserved
Bit 5
= Semaphore for Completed POST
Bit 4 = Semaphore for 0 Volt POST (not currently used)
Bit 3 = Semaphore for already in SCU menu
Bit 2 = Semaphore for already in PM menu
Bit 1 = Semaphore for SCU menu call pending
Bit 0 = Semaphore for PM menu call pending
40h-7Fh Definitions for these locations vary depending on the chipset.
6.12 EEPROM saved CMOS Setup
The EEPROM has different functions, as listed below:
»
Backup of the CMOS-Setup values
»
Storing system information (i.e., version, production date, customization of the board, CPU type)
»
Storing user/application values
The EEPROM updates automatically after exiting the BIOS setup menu. The system will also operate without any CMOS
battery. While booting, the CMOS is automatically updated with the EEPROM values.
Press the ESC-key while powering on the system before the video shows the BIOS message and the CMOS will not be
updated. This is helpful, if wrong parameters have been stored in the EEPROM and the BIOS setup does not start.