Technical Reference Guide
CHAPTER 4 SYSTEM SUPPORT.........................................................................................................
4.1
INTRODUCTION.................................................................................................................. 4-1
4.2
PCI BUS OVERVIEW ........................................................................................................... 4-2
4.2.1
PCI CONNECTOR......................................................................................................... 4-3
4.2.2
4.2.3
PCI BUS TRANSACTIONS........................................................................................... 4-5
4.2.4
OPTION ROM MAPPING ............................................................................................. 4-8
4.2.5
PCI INTERRUPT MAPPING ......................................................................................... 4-9
4.2.6
4.2.7
PCI CONFIGURATION............................................................................................... 4-10
4.3
AGP BUS OVERVIEW ....................................................................................................... 4-11
4.3.1
BUS TRANSACTIONS................................................................................................ 4-11
4.3.2
AGP CONFIGURATION ............................................................................................. 4-14
4.3.3
AGP CONNECTOR..................................................................................................... 4-15
4.4
ISA BUS OVERVIEW......................................................................................................... 4-16
4.4.1
ISA CONNECTOR ...................................................................................................... 4-17
4.4.2
ISA BUS TRANSACTIONS......................................................................................... 4-18
4.4.3
DIRECT MEMORY ACCESS...................................................................................... 4-20
4.4.4
INTERRUPTS.............................................................................................................. 4-23
4.4.5
INTERVAL TIMER..................................................................................................... 4-27
4.4.6
ISA CONFIGURATION............................................................................................... 4-27
4.5
4.6
4.7
4.7.1
SYSTEM I/O MAP ...................................................................................................... 4-46
4.7.2
GPIO UTILIZATION ................................................................................................... 4-47
4.8
4.8.1
4.8.2
PASSWORD PROTECTION........................................................................................ 4-52
4.8.3
I/O SECURITY ............................................................................................................ 4-53
4.8.4
USER SECURITY........................................................................................................ 4-53
4.8.5
TEMPERATURE SENSING ........................................................................................ 4-54
4.8.6
SMART COVER LOCK............................................................................................... 4-55
4.8.7
4.8.8
POWER MANAGEMENT ........................................................................................... 4-56
5.1
INTRODUCTION.................................................................................................................. 5-1
5.2
ENHANCED IDE INTERFACE ............................................................................................ 5-1
5.2.1
IDE PROGRAMMING................................................................................................... 5-1
5.2.2
IDE CONNECTOR ........................................................................................................ 5-8
5.3
5.3.1
5.3.2
5.4
SERIAL INTERFACES ....................................................................................................... 5-14
5.4.1
RS-232 INTERFACE ................................................................................................... 5-14
5.4.2
iv
Compaq Deskpro EN Series of Personal Computers
Desktop and Minitower Form Factors
Third Edition-- September1998