
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
Содержание 740
Страница 1: ...Intel740 Graphics Accelerator Design Guide August 1998 Order Number 290619 003 ...
Страница 9: ...1 Introduction ...
Страница 10: ......
Страница 13: ...2 Intel740 Graphics Accelerator Addin Card Design ...
Страница 14: ......
Страница 40: ...Addin Card Design 2 26 Intel740 Graphics Accelerator Design Guide ...
Страница 57: ...3 Intel740 Graphics Accelerator 3 Device AGP Motherboard Design ...
Страница 58: ......
Страница 86: ...3 Device AGP MotherBoard Design 3 28 Intel740 Graphics Accelerator Design Guide ...
Страница 128: ...4 Thermal Considerations ...
Страница 129: ......
Страница 131: ...Thermal Considerations 4 2 Intel740 Graphics Accelerator Design Guide ...
Страница 132: ...5 Mechanical Information ...
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Страница 139: ...Mechanical Information 5 6 Intel740 Graphics Accelerator Design Guide ...
Страница 140: ...6 Third Party Vendors ...
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Страница 144: ...A Application Notes ...
Страница 145: ...Intel740 Graphics Accelerator Application Note 653 Thermal Design Considerations April 1998 Order Number 292211 002 ...
Страница 172: ...Intel740 Graphics Accelerator Thermal Design Considerations 24 Application Note 653 ...
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Страница 185: ...B Reference Information ...
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Страница 187: ...PC SGRAM Specification Revision 0 9 February 1998 Order Number Not Applicable ...
Страница 216: ...PC SGRAM Specification 26 Revision 0 9 ...