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Advantech SOM-Express Design Guide
62
Chapter 5 Carrier Board Design Guidelines
Figure 5-24 IDE Master/Slave Handshake Signals Connection
5.6.2.2 UDMA Support
Some SOM-Express modules support UDMA 33 data transfer mode. If an advanced
IDE data transfer mode such as UDMA 66 is required, it requires a special 80-
conductor IDE cable for signal integrity.
For UDMA 66 support, it is recommended the IDE bus and total cable length of
carrier board do not exceed 13 inches.
Figure 5-25 IDE Bus Trace on Carrier Board and Cable
5.6.2.3 IDE interface connections
All necessary pull up/down resistors are implemented on the SOM module and do
not need to be implemented on the carrier board.
SOM-
Express
IDE bus
IDE cable
Total Max.
Length 13 inches
Carrier Board