DDR3-reset

Hello,
We are working on Zynq(7020-400-pin package), designing our own customized board. I am referring to the new schematic of microzed(28-jan-2014). I found that i should pull down the DDR3-reset# to ground through 40.2E resistor, but when it referred to UG933 page 62, i found that the DDR3-reset pin should be pull down to ground through 4.7K. please any one help me which one should i follow.

Thanks and Regards
Arjun Krishna

0 e14 Contributor over 12 years ago

At the time we designed MicroZed, there was an error in UG933 that said DRST_B should be pulled up via 40-ohms to Vtt. We had suspicions that this was wrong, so we designed the MicroZed with a jumper so we could easily switch with just a BOM change.

Xilinx finally clarified and corrected UG933 in July 2013, which was after Rev B was built, but before Rev C. I believe all Revisions C and later will have pull-down to ground, the schematic just needs to be updated to reflect that.

-Gary
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0 arjunbk09 over 12 years ago in reply to e14 Contributor

Thank you for the information Gary.
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