MC9S08RE16 - i/o port values in stop mode

[stevec]

I want to put a MC9S08RE16 into stop mode 2 or 3 and wish to keep the i/o ports in their pre stop state (they enable some power supplies that I want retained). The manual says the i/o states are unchanged in stop3 mode. In stop2 mode it says they are latched. What exactly does this mean? I can't use stop1 as this turns the i/o lines off (low) which will turn off my external regulators. From what I can see stop2 and stop3 are similar in that they retain the i/o state and only differ in how the uP comes out of stop mode. Is this correct?

Steve

--
Alban Edit: FSL Part Number must figure in Message Subject line.


Message Edited by Alban on 2007-07-25 12:51 PM

[stevec]

Ok think I've answered this myself after more digging in the Reference manual.
Another question though. When exiting stop3 mode via the KBI the processor uses the appropriate interrupt vector. Where does it return to when it exits the interrupt?  Is it the instruction following the STOP instruction which put it to sleep?

[peg]

They're not real clear on this either, are they?

I would assume you are correct based on "where else would it execute from" and if it was something different then they probably would tell you.

It seems stop modes vary quite a bit between even different S08 derivatives so no conclusions can be drawn from experience or manuals from others.

Time to fire up that simulator and hope they have all the differences covered there!