LED blink using hardware counter

Code

while : true {
    start_counter();
    while : read_counter() < 200000000 {
        digital_write(P1_31, true);
    }
    stop_counter();

    start_counter();
    while : read_counter() < 200000000 {
        digital_write(P1_31, false);
    }
    stop_counter();
}

• Following code works on PocketBeagle, to use on other boards, please change the pins accordingly.

Explanation

This code runs a never ending while loop, since it is while : true. Inside while it starts the counter, then in a nested while loop, which runs as long as read_counter returns values less than 200000000, so for 200000000 cycles, HIGH is written to header pin P1_31, and after the while loop ends, the counter is stopped.

Similarly counter is started again, which runs as long as read_counter returns a value less than 200000000, so for 200000000 cycles, LOW is written to header pin P1_31, and after the while loop ends, the counter is stopped.

This process goes on endlessly as it is inside a never ending while loop. Here, we check if read_counter is less than 200000000, as counter takes exactly 1 second to count this much cycles, so basically the LED is turned on for 1 second, and then turned off for 1 second. Thus if a LED is connected to the pin, we get a endlessly blinking LED.