Intel ECB-865 user manual 2.3.2DRAM Interface, 2.3.3Multiplexed AGP and Display Cache Interface

User’s Manual

2.3.2DRAM Interface

The GMCH integrates a system memory controller that supports a 64-bit 100/133 MHz SDRAM array. The only DRAM type supported is industry standard Synchronous DRAM (SDRAM). The SDRAM controller interface is fully configurable through a set of control registers. The DRAM controller supports the following features:

DRAM type: Support for x8 and x16 SDRAM device width, Unbuffered, and Non-ECC SDRAM only

Memory Size: 32 MB to 512 MB using 16Mb/64Mb/128Mb/256Mb technology

Addressing Type: Asymmetrical addressing only

DRAM Speeds: 100/133 MHz for synchronous memory (SDRAM).

Memory Modules supported: Up to 3 double-sided DIMMs at 100 MHz system memory bus; Up to 2 double sided or 3 single-sided DIMMs at 133 MHz system memory bus.

Suspend to RAM support

2.3.3Multiplexed AGP and Display Cache Interface

The Intel 82815 GMCH multiplexes an AGP interface with a display cache interface for internal 3D graphics performance improvement. The display cache is used only in the internal graphics.

When an AGP card is installed in the system, the GMCH internal graphics will be disabled and the AGP controller will be enabled.

2.3.3.1AGP Interface

A single AGP connector is supported by the GMCH AGP interface. The AGP buffers operate in one of two selectable modes in order to support the AGP Universal Connector:

3.3V drive, not 5 Volt safe: This mode is compliant to the AGP 1.0 and 2.0 specifications

1.5 V drive, not 3.3 Volt safe: This mode is compliant with the AGP 2.0 specification.

The following table shows the AGP Data Rate and the Signaling Levels supported by the GMCH.

8ECB-865 User’s Manual