
82801AA and 82801AB
Datasheet
vii
5.2
LPC Bridge (with System & Management Functions) (D31:F0)....................5-4
5.2.1
LPC Interface...................................................................................5-4
5.2.1.1
LPC Cycle Types..............................................................5-5
5.2.1.2
Start Field Definition.........................................................5-5
5.2.1.3
Cycle Type / Direction (CYCTYPE + DIR)........................5-6
5.2.1.4
SIZE..................................................................................5-6
5.2.1.5
SYNC................................................................................5-6
5.2.1.6
SYNC Time-out ................................................................5-7
5.2.1.7
SYNC Error Indication......................................................5-7
5.2.1.8
LFRAME# Usage..............................................................5-7
5.2.1.9
I/O Cycles.........................................................................5-9
5.2.1.10 Bus Master Cycles............................................................5-9
5.2.1.11 Configuration and ICH Implications..................................5-9
DMA Operation (D31:F0)..............................................................................5-9
5.3.1
Channel Priority .............................................................................5-10
5.3.2
Address Compatibility Mode ..........................................................5-11
5.3.3
Summary of DMA Transfer Sizes ..................................................5-11
5.3.4
Autoinitialize...................................................................................5-12
5.3.5
Software Commands .....................................................................5-12
PCI DMA.....................................................................................................5-13
5.4.1
PCI DMA Expansion Protocol........................................................5-13
5.4.2
PCI DMA Expansion Cycles ..........................................................5-14
5.4.3
DMA Addresses.............................................................................5-15
5.4.4
DMA Data Generation....................................................................5-15
5.4.5
DMA Byte Enable Generation........................................................5-15
5.4.6
DMA Cycle Termination.................................................................5-16
LPC DMA....................................................................................................5-16
5.5.1
Asserting DMA Requests...............................................................5-16
5.5.2
Abandoning DMA Requests...........................................................5-17
5.5.3
General Flow of DMA Transfers ....................................................5-17
5.5.4
Terminal Count ..............................................................................5-18
5.5.5
Verify Mode....................................................................................5-18
5.5.6
DMA Request Deassertion ............................................................5-18
5.5.7
SYNC Field / LDRQ# Rules...........................................................5-19
8254 Timers (D31:F0).................................................................................5-20
5.6.1
Timer Programming .......................................................................5-20
5.6.2
Reading from the Interval Timer ....................................................5-21
8259 Interrupt Controllers (PIC) (D31:F0)...................................................5-23
5.7.1
Interrupt Handling ..........................................................................5-23
5.7.2
Initialization Command Words (ICWx)...........................................5-25
5.7.3
Operation Command Words (OCW)..............................................5-26
5.7.4
Modes of Operation .......................................................................5-26
5.7.5
Masking Interrupts .........................................................................5-29
5.7.6
Steering PCI Interrupts ..................................................................5-29
Advanced Interrupt Controller (APIC) (D31:F0)..........................................5-30
5.8.1
Interrupt Handling ..........................................................................5-30
5.8.2
Interrupt Mapping...........................................................................5-30
5.8.3
APIC Bus Functional Description...................................................5-31
5.8.3.1
Physical Characteristics of APIC....................................5-31
5.8.3.2
APIC Bus Arbitration.......................................................5-31
5.8.3.3
Bus Message Formats....................................................5-32
5.3
5.4
5.5
5.6
5.7
5.8