[gta02-core] Memory Schematics
Werner Almesberger
werner at openmoko.org
Mon Jun 22 07:23:17 CEST 2009
Luke Duncan wrote:
> Fixed. I placed the caps next to the pins because it made it more clear for
> me.
Hmm, they look slightly incorrect. They ought to be close to the
respective pairs of power pins, so any pair of equal-sized caps
connecting to the same set of pins is suspicious.
However, GTA02 has them in an even less likely configuration:
http://people.openmoko.org/werner/sdram-bypass.png
Possible peripheral pairings would be
- VDD-VSS: A7-A3, R7-R3
- VDDQ-VSSQ: E1-{C,D}1, L1-{M,N}1, {C,D}9-E9, {M,N}9-L9
If we wanted to bypass each pair of powers close to the package,
we'd end up with six caps (plus the big one that forms an LC
filter with the bead). Unfortunately, the data sheet makes no
recommendations regarding bypassing :-(
- Werner
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