We use MC9s12D64 our project. I need 20MHz bus speed. And I know that there is two alternatives for this:
1- Using 40MHz xtal osc. And this divided by two. So I will have 20 MHz bus speed.
2- Using for example 10 MHz xtal and by using PLL I will have 20 MHz bus speed.
Can anybody explain me what is the difference between this two choices. For example EMC chacarteristics of product which one is better. Or when communicating more than one uC by SCI, IIC or CAN bus is there any problem using PLL (for example baud rate differences...).