Texas Instruments MSP50C614 manual Implementation Details

	Implementation Details
cmm_func	iport(int x); // read a port
int i,j,k,l;	// various temp and loop variables
int x[4];	// array holding the correct key sequence
int locked=1;	//variable returned by lock()

cmm_func lock(){

x[0]= 0xEF; //MS7 x[1]= 0xBF; //MS9 x[2]= 0xEF; //MS7 x[3]= 0x7F; //MS10

locked=0;

cport('B', 0xFF); //Configure port B as output. //Port B is the LED's on the //code development unit.

oport('B', 0xFF);		//Turn off all 4 LEDs.
for (i=0; i<4; i++){		// loop through all required inputs
k=iport('F');	// read port F
while( k == 0xFF ){		// wait for keypress
k=iport('F');		// read port F
oport('B', k);		// output the value from F
wait(100);		// delay 100ms for key debouncing
}
l=iport('F');		// read port F
while( l != 0xFF ){		// wait for key release
wait(100);		// delay 100ms for key debouncing
l=iport('F');		// read port F
}
if (x[i] != k) {		// compare to correct input
locked=1;		// if incorrect then lock and return
return locked;

}

} // end for (i=0; i<4; i++){

return locked; // If the program reaches this return then all inputs were correct

// and the main program can unlock.

}

cmm_func main() // code begins executing here after init614.asm is executed

{

asminit(); // configure everything

cport('B', 0xFF); //configure port B as output for (j=0; j<1000; j++){ //semi±infinite loop

if (lock()){ // get input and see if correct

//if lock()==1 the input was incorrect

//The LED's are then flashed and the program repeats. oport('B', 0x00);

wait(100); oport('B', 0xFF); wait(100); oport('B', 0x00); wait(100); oport('B', 0xFF);

Code Development Tools 5-65