The µVision3 accepts binary constants with a 'y' or 'Y' as a suffix. The following lines will not be compiled correctly: SSPCR0 = (1111y<<0)|//16 data bits (0<<4)| //SPI (0<<6)| //Clock out polarity (1<<7)| //Clock out phase (1<<8); //Clock rate What is the reason for the message "error C25: syntax error near 'y'"? How do I sign binary constants in program code? I already tried "1111Y", "1111b" and "1111B". No success. Regards Martin