There seem to be several pins that require the same connections. For example pin's 12, 24, and 54 should all be connected to VDDCORE. And pins 18, 45, and 58 should all be connected to VDDIO. Why don't they just do it all internal on the chip?

pin 12 VDDCORE / pin 24 VDDCORE / ping 54 VDDCORE

pin 18 VDDIO / pin 45 VDDIO / pin 58 VDDIO

Thanks for any info!

-Henk Visser

Hello,

just to keep an equipotentiality power supply level in the die.

Rgds
JP

To add a bit more info to JP's answer:

traces on a chip have pretty high resistance and if you have only one supply or ground pin and you run it all around the chip neither the ground nor the supply will be what it should be. Tons of spikes and completely different voltage levels.

In addition the lines have to be made very wide to avoid electro migration which increases the die size (= cost).

Juergen

Thanks for the posts gentlemen! Excellent!

-Henk

If I have power going to one pin on the processors 1 decoupling cap would be suffiecient. But since I have this same voltage going to muliple pins should I have caps at each pin? Or maybe 1 cap right before the all spit off.

Thanks.

-Henk

Better to have one decoupling cap per pin !!!!! Take a look at the Evaluation Board schematics

Aaron,

Looking at the Power Decoupling section in the schematic I was not sure on how to approach this becaue I want each decoupling cap as close to the pins as possoble but they group all the caps together and it was throwing me for a loop!

Thank you!