Hi Isaac, Use the following sentence to increase stack to 512bytes #build(stack=3D512) You are right; they just adapted the baseline C compiler for PIC24. Actuall= y their current versions doesn't implement any optimization control, even if the GUI apparently allows you to. The compiler has some basic optimization embedded but will not allow you to switch it on or off. Their 8 bits compiler is better in that regard. HTH Ariel Rocholl -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Isaac Marino Bavaresco It defines a very small stack (128 bytes), which it uses only for return addresses (like small PICs). I need to enlarge the stack to at least 256 bytes, because my MPLAB C30 code uses local variables on stack. .... even at maximum optimization level. It seems that CCS picked their compiler for small PICs and just "adapted" i= t for PIC24 devices. I always had CCS as a high-grade compiler by the words o= f others. Now I seriously doubt if I would ever use it. .... --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .