System Memory Design Guidelines (DDR-SDRAM)
R
Intel
®
855PM Chipset Platform Design Guide
157
Figure 90. RCVEN# Signal Routing Example
Odem
Clocks
RCVEN# on
same internal
layer as clocks
Vias
MCH-M
Pin
RCVEN# on
external layer
Intel 855PM MCH-M
Odem
Clocks
RCVEN# on
same internal
layer as clocks
Vias
MCH-M
Pin
RCVEN# on
external layer
Intel 855PM MCH-M
Intel 855PM MCH
MCH
Pin
Odem
Clocks
RCVEN# on
same internal
layer as clocks
Vias
MCH-M
Pin
RCVEN# on
external layer
Intel 855PM MCH-M
Odem
Clocks
RCVEN# on
same internal
layer as clocks
Vias
MCH-M
Pin
RCVEN# on
external layer
Intel 855PM MCH-M
Intel 855PM MCH
MCH
Pin
6.1.6.
Support for “DDP Stacked” SO-DIMM Modules
Simulations have been performed to verify the suitability of the DDR layout and routing guidelines to
support the use of 512-Mbit technology-based (two 256-Mbit dies within the same package), “DDP
stacked”, 2x8 SO-DIMM memory modules on Intel 855PM chipset based platforms. For the purpose of
this discussion, the term “DDP stacked” is used to refer to DDP SDRAM based 2x8 SO-DIMM memory
modules. Based on these simulations, the current routing guidelines can support this type of stacked
memory device. Other stacked devices have not been simulated and therefore cannot be recommended.
Please see Section 6.1.4 for clock signal group related routing updates.