#pragma SRC unsigned int ScanKey(void) /* test case to provide */ { /* compilability */ return(0x0002); } unsigned char ScanKeySingle(void) { unsigned int key16; unsigned char key8 = 16; /* get the key scan vector */ key16 = ScanKey(); /* exit early if no keys active */ if(key16 == 0x0000) { return(0x80); /* show no key */ } /* scan the 16 bit key vector with 1's for keys pressed */ do { if(key16 & 0x8000) /* if a key vector bit is set */ { if(key16 & 0x7FFF) /* if another bit is set */ { /* show multiple key pressed */ return(0x10); } else { /* singular key found */ return(--key8); } } key16 <<= 1; /* shift the key bits left */ } while(--key8); /* default exit for no kwy pressed */ return(0x80); /* Note that code never will get here */ } /* due to the early exit check at beginning */