Q: Why are there no series resistors on all of the signals to the DDR memory on the iMX31 LITEKIT?

A:
The i.MX31 LITEKIT excludes the series resistors on the DDR interface for these reasons:
• Freescale testing on the IMX31 ADS kit found that series resistors provided little to no signal integrity improvement on DDR lines.
• Low power (mobile) DDR has drive strength control on chip.
• i.MX31 CPU has some drive strength control on DDR lines.
• All EMC compliance testing passed without series resistors.

PRODUCTS Included:
iMX31