Stefan Waldschmidt / Mbed OS Test_GPIO-out_Toggle_Time

Test maximal GPIO output performance by toggling a GPIO output pin as fast as possible.

This mbed program creates a thread with Realtime Priority to do nothing but to toggle a GPIO output as fast as possible.

Measurements are performed on a NUCLEO-F767ZI board https://os.mbed.com/platforms/ST-Nucleo-F767ZI/.

  • STM32F767ZIT6 @ 216 MHz
  • Duration of high or low phases: 4 nsec - 10 nsec (resulting is something from 50 MHz to 125 MHz)

main.cpp

Committer:
stefanwaldschmidt
Date:
2019-05-13
Revision:
0:f122acadb07b

File content as of revision 0:f122acadb07b:

/*
   Test GPIO-output toggle time

   Hardware: NUCLEO-F767ZI
     STM32F767ZIT6 @ 216 MHz
   Libraries:
     mbed-os-5.12.3
   Measured gpio_out frequency
   * total period: 8 nsec - 20 nsec (125 MHz - 50 MHz)
*/

#include "mbed.h"

DigitalOut gpio_out(PC_8);

void run()
{
    while (true) {
        gpio_out = 1;
        gpio_out = 0;
        gpio_out = 1;
        gpio_out = 0;
    }
}

int main()
{
    Thread *thread  = new Thread(osPriorityRealtime);

    thread->start(run);

    while (true) {
        wait(0.1); // 100 ns
    }
}