Ignition on!

Diving straight into code, you can blink a LED on your target board with a few lines of code:

// Blink the first platform LED.

#include "libplatform/platform.h"

void
main(void)
{
  // Initialize platform.
  platform_initialize();

  // Blink first LED forever.
  for (;;)
    {
      platform_write_led(0, 1);     // LED on
      platform_spin_delay_ms(500);  // Wait
      platform_write_led(0, 0);     // LED off
      platform_spin_delay_ms(500);  // Wait
    }
}

Hopefully, this should be self-explanatory, but here are some noteworthy items:

• All Platform Library functions are prefixed with "platform".
• platform_initialize sets up the board and processor for the Platform Library. You need to call this before using any other Platform Library function. See platform_initialize.
• platform_write_led(x, y) writes x to LED y. See platform_write_led.
• platform_spin_delay_ms(x) delays execution for x milliseconds by busy-waiting in a loop. See platform_spin_delay_ms.
• Which LED blinks on your target board depends upon the target board, obviously—consult the documentation for the Platform Library on your target board for details of LED numbering.

By the way...

This does the job, but isn't the kindest way to blink a LED. Because this example uses platform_spin_delay_ms to pause between changing the LED state, the processor is active all the time, burning cycles, waiting for the right moment to continue. There is a better way…

You can use ctl_delay, rather than platform_spin_delay_ms, to delay the user task and let other tasks run. If you do this, you are being much kinder to the tasking system, and in this case the processor is put to sleep whilst waiting.