Advantech SOM-ETX Design Guide
5.4.2.2 ISA vs. Other Buses
Personal computer manufacturers are eliminating the ISA bus from new products.
Although this action will not have an immediate impact on embedded applications,
there is a clear trend to migrate ISA bus functions to the PCI bus or to other
interfaces such as USB.
These newer interfaces are more efficient than the ISA bus and easier for operating
systems to manage. They also have fewer resource limitations. Designers should
consider PCI and USB as alternatives to new ISA bus implementations, or as an
eventual upgrade path from ISA designs.
5.4.3 Layout Guideline
5.4.3.1 ISA BUS necessary Pull up resistors location
All necessary pull up resistors were implemented in SOM-ETX. CSB do not need to
consider terminate resistors design.
SOM-ETX
On Board Chipset
SOM-
ETX
Connector
X2
VCC
Necessary
Pull-Up
Resistor
Base
Board ISA
Connector
SOM-ETX
ISA BUS
ISA BUS
Figure 5-14 ISA BUS necessary Pull up resistors location
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Chapter 5 Carrier Board Design Guidelines
