Hi, What does     ( void ) ulCriticalNesting; do?  It is at the bottom of the portSAVE_CONTEXT macro for ARM7_LPC2000, where at the top of the macro I see     extern volatile unsigned portLONG ulCriticalNesting; Thanks in advance, John Alfredo

I have not checked the code, but if its where I think it is then it is just to prevent the compiler generating a warning about an unused parameter.  The parameter is in fact used, but only from inline asm where the compiler does not see it. Regards.