What frequencies are when the pcb design get tricky?
The project on my hand now is a 20MHz SPI bus shared between four devices,now I have problems with this project and look for general guidelines.
1.How to prevent long traces from radiating when frequencies increase? Are striplines and coax the way to go?
2.Do you have any guidelines as far as trace length vs frequency? I assume that about 3 inch traces are fine with 20MHz, but what is the general case?
3.What is the RF characteristic impedance of a typical microcontroller output stage, anyway?
Please feel free to tell me anything you know and I am missing.