Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Cache Memory Operation .................... 2-2
Cacheable Address Space .................... 2-3
Bus Adapter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
Keyboard/Mouse Connector . . . . . . . . . . . . . . . . . . . . . 2-4
Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Scan Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
Keyboard ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Displayable Characters and Symbols .............. 2-7
Hard Disk Drive Connector ..................... 2-8
External Bus Connector ....................... 2-8
UltraSlim Bay Connector ..................... 2-11
Diskette Drive and Controller ................... 2-14
Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
ROM Subsystem . . . . . . . . . . . . . . . . . . . . . . . . 2-15
RAM Subsystem . . . . . . . . . . . . . . . . . . . . . . . . . 2-15
System Memory Map ...................... 2-16
System Board Memory for the DIMM Connectors ..... 2-17
RT/CMOS RAM . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
RT/CMOS Address and NMI Mask Register (Hex 0070) 2-19
RT/CMOS Data Register (Hex 0071) ........... 2-19
RT/CMOS RAM I/O Operations .............. 2-20
CMOS RAM Configuration ................. 2-24
Miscellaneous System Functions and Ports .......... 2-28
Nonmaskable Interrupt (NMI) ................. 2-28
System Control Port A (Hex 0092) .............. 2-29
System Control Port B (Hex 0061) .............. 2-30
Power-On Password . . . . . . . . . . . . . . . . . . . . . . 2-31
Other Passwords . . . . . . . . . . . . . . . . . . . . . . . . 2-31
Selectable Drive-Startup Sequence .............. 2-32
Hardware Compatibility . . . . . . . . . . . . . . . . . . . . . . 2-33
Error Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34
Copyright IBM Corp. 1998 2-1