Intel 740 User Manual

3 Device AGP MotherBoard Design
3-18
Intel740™ Graphics Accelerator Design Guide
The clock lines were tuned as detailed in table Table 3-9 to ensure that no clock skew exceeding
0.75 ns occurred. Note that in the case of gclks, the load is the AGP connector.
3.2.4 Intel740™ Graphics Accelerator Memory Layout and
Routing Guidelines
The Intel740 graphics accelerator integrates a memory controller that supports a 64-bit memory
data interface. SGRAM can be used in addition to SDRAM, if it is configured to perform as an
SDRAM. The Intel740 graphics accelerator generates the Row Address Strobe (SRAS[A:B]#),
Chip Selects (CS0[A:B]#, CS1[A:B]#), Column Address Strobe (SCAS[A:B]#), Byte Enables
(DQM[0:7]#), Write Enables (WE[A:B]#), and Memory Addresses (MA). The memory controller
interface is fully configurable through a set of control registers.
Eleven memory address signals (MAx[10:0]) allow the Intel740™ graphics accelerator to support
a variety of commercially available components. Two SRAS# lines permit two 64-bit wide rows of
SDRAM. All write operations must be one Quadword (QWord). The Intel740 graphics accelerator
supports memory up to 100 MHz.
Rules for populating a Intel740 graphics accelerator Memory:
•
SDRAM and SGRAM components can be mixed.
•
The DRAM Timing register, which provides the DRAM speed grade control for the entire
memory array, must be programmed to use the timings of the slowest memories installed.
Possible DRAM and system options supported by the Intel740 graphics accelerator are shown in
Table 3-10.
There are several groups of signals within the memory bus with layout restrictions.
Table 3-9. Clock Segment Solution Space
Clock Net Driver to resistor lengths Resistor to Load lengths
Gclkin 0.4-0.5 Inches 6.2-6.4 Inches
Gclks 0.3-0.4 Inches 4.4-4.6 Inches
Gclk740 0.4-0.5 Inches 6.4-6.6 Inches
Table 3-10. Supported Memory Options (Other Memory Options Are Not Supported)
SDRAM/
SGRAM
Technology
SDRAM/
SGRAM
Density
SDRAM/
SGRAM
Width
Addressing Address Size
Local Memory
Size
Row Column Min Max
8 Mbit 256K 32 Asymmetric 10 8 2MB 4MB
16Mbit 512K 32 Asymmetric 11 8 4MB 8MB
16Mbit 1M 16 Asymmetric 12 8 8MB 8MB

Intel 740 Specifications

General

Brand	Intel
Model	740
Category	Video Card
Language	English