In SX Microcontrollers, SX/B Compiler and SX-Key Tool, g_daubach wrote:

Hi William,

in general, multilayer caps are the better choice because of less parasitic series inductance. To avoid additional parasitic series inductance, it is necessary to keep the leads as short as possible (SMTs are best as they don't have leads), and to place the cap as close as possible to the supply pins as longer PCB traces would add inductance again. You can't say as a rule of thumb that a higher cap (say 470 nF) is better than a 100 nF) cap - sometimes, smaller values even do better.

I can only agree with Michael that connecting all supply pins helps to reduce the supply impedance, and four filter caps, each of them close to a pair of supply pins are by no means an overkill. In case you did not, please check the other thread (EMI Failure) I had mentioned in my previous message. There you find a lot more information about this topic, so it is not necessary repeating it here.

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