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Intel® 82845 MCH for SDR Datasheet 3
1 Introduction........................................................................................................................11
1.1 Terminology and Notations................................................................................... 11
1.2 Reference Documents.......................................................................................... 13
1.3 Intel® 845 Chipset System Architecture................................................................ 14
1.4 Intel® 82845 MCH Overview .................................................................................14
1.4.1 System Bus Interface ............................................................................15
1.4.2 System Bus Error Checking ..................................................................15
1.4.3 System Memory Interface .....................................................................16
1.4.4 AGP Interface........................................................................................16
1.4.5 Hub Interface.........................................................................................17
1.4.6 Intel® MCH Clocking..............................................................................17
1.4.7 System Interrupts ..................................................................................18
1.4.8 Powerdown Flow................................................................................... 18
2 Signal Description..............................................................................................................19
2.1 System Bus Signals.............................................................................................. 21
2.2 SDR SDRAM Interface Signals.............................................................................23
2.3 Hub Interface Signals............................................................................................23
2.4 AGP Interface Signals...........................................................................................24
2.4.1 AGP Addressing Signals....................................................................... 24
2.4.2 AGP Flow Control Signals.....................................................................25
2.4.3 AGP Status Signals...............................................................................25
2.4.4 AGP Strobes Signals.............................................................................26
2.4.5 AGP/PCI Signals................................................................................... 26
2.5 Clocks, Reset, and Miscellaneous Signals ...........................................................28
2.6 Voltage Reference and Power Signals .................................................................29
2.7 Reset States During Reset ...................................................................................30
3 Register Description ..........................................................................................................31
3.1 Register Terminology............................................................................................31
3.2 PCI Bus Configuration Space Access...................................................................32
3.2.1 Standard PCI Bus Configuration Mechanism........................................33
3.2.2 Routing Configuration Accesses ...........................................................33
3.3 I/O Mapped Registers........................................................................................... 34
3.3.1 CONF_ADDR—Configuration Address Register ..................................34
3.3.2 CONF_DATA—Configuration Data Register.........................................36
3.4 Memory-Mapped Register Space .........................................................................36
3.4.1 DRAMWIDTH—DRAM Width Register .................................................37
3.4.2 DQCMDSTR—Strength Control Register (SDQ and CMD
Signal Groups) ......................................................................................38
3.4.3 CKESTR—Strength Control Register (SCKE Signal Group) ................39
3.4.4 CSBSTR—Strength Control Register (SCS# Signal Group).................40
3.4.5 CKSTR—Strength Control Register (Clock Signal Group) ...................41
3.4.6 RCVENSTR—Strength Control Register (RCVENOUT
Signal Group) ........................................................................................42