It's a general question about series resistors in this type of application but I will use an example to make it easier to understand.
I have a LCD controller which uses an SDRAM, we can read a lot on the internet and it is common knowledge that you can put series resistors on numeric signals to increase the rising and falling time. For example, if my controller emits a clock in the direction of the SDRAM, the resistor has to be close to the controller. Since this resistor is meant to limitate the current which will flow through the parasitic capacitor at the input,I don't understand why the placement is important?
The question is : Why does this resistor has to be as close as possible to the source of the signal? What is the difference if it is close to the destination?