32 single chip microcomputer has more than one variable Used in C

Way ： Normally define a variable in other files （ Can be initialized ）, The main function or other functions need to use this variable . Add... Before the variable definition extern（ Uninitialized ）

key.c In file

uint16_t a;

main.c In file

int main(void)

{

extern uint16_t a;

}