New C18 3.0+ Compatible FRC Code

[Alan Anderson]

Originally Posted by sumadin

Kevin,

While we're looking at the new code, what is the difference between interrupts 1,2 and 3-6? I read the encoders readme, and I understand how they differ. However, I haven't seen any documentation about the interrupts themselves. Could you please explain me how (if it all) they differ?

Digital inputs 1 and 2 each go to separate interrupt circuits. They can be configured to cause an interrupt on either a low-to-high or high-to-low transition of the input. The interrupt service routine can inspect individual flags to determine which input caused the interrupt.

Digital inputs 3-6 all go together to a third interrupt circuit, and automatically cause an interrupt on any input transition. There's only one flag to say that "something changed" on those pins. In order to determine which of the four inputs is responsible, the software has to do its own bookkeeping to compare the previous input state against the present one.

That's a simple explanation. There's more detail in the PIC manual if you want it.