What is the difference between 1 and 1UL in ARM's keil compiler?
Keil's common problems need to be written like this: LPC _ PINCON-& gt；; pinsel 3 | =(unsigned int)( 1 & lt； & lt3 1); Or LPC _ pincon->; PINSEL3 |= (unsigned long integer) (1< & lt3 1); Keil default data is signed, because your (1