PCB

Are there any cautions I should observe regarding circuit design (pattern design)?

Regarding the clock circuit, keep the wiring distances as short as possible and do not cross port wiring, in order to avoid malfunction.
Please refer to the section "System clock oscillator" in the user's manual.

When information not listed in data sheets and user's manuals, such as noise reports, etc., is required, please contact your authorized NEC Electronics distributor.

Also, regarding noise, there are two viewpoints, EMS and EMI.
When inquiring about noise, please specify which.

What are the pad dimensions of the microcontroller's PCB?

The IC package documents are published on the NEC Electronics homepage.
Package/mounting information is listed in the following pull-down menu.

PRODUCTS >> Japan (English site) >> IC Package Items >> Package Type.
(The PCB pad dimensions are listed under "Land Pattern" there.)