Hi! I'm have foloving problem with AVR optimizatin. Тhe code in optimization label higher 0 compiling in: while(Data_Num>22); +00000528: 91800C83 LDS R24,0x0C83 Load direct from data space +0000052A: 3187 CPI R24,0x17 Compare with immediate +0000052B: F7F0 BRCC PC-0x01 Branch if carry cleared // Branch on compare without modifing value while()?? Value Data_Num change in interupt and in memory 0xC83 correct value, but compare with fixed on input value?? Can you Help me? With best regards, Lubomudrov Alexey. P.S. If it is not problem can you send mee example of using class and struct in GCC for Atmel AVR. Thank! -- Сколько ваших знакомых в МойКруг.ру? http://moikrug.ru/