Toggles all the 8051 ports ( P0, P1, P2 and P3 ) on/off and generates a square wave with a period of 2 milliseconds ( 500 Hertz ).
Toolkit:SDCC 8051 Development System
Location:/bipom/devtools/SDCC/examples/io/
main() { serinit(19200); /* Infinite Loop */ for( ;; ) { /* Reset all the ports */ P0 = 0; P1 = 0; P2 = 0; P3 = 0; /* Delay 1 millisecond */ delay(1); /* Set all the ports */ P0 = 0xFF; P1 = 0xFF; P2 = 0xFF; P3 = 0xFF; /* Delay 1 millisecond */ delay(1); } }