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Unable to see LED toggling (programming MCU in C++) ?

+1 vote
asked Dec 12, 2021 by Areeb Sherjil (1,920 points)

I made this code that turns off all LEDs and then deletes data. Upon deleting the data it turns on the green LEDs. However, when the code runs the user cannot 'see' the green leds turning off and then on. Is this because the MCU does these commands so fast that a human eye cannot see it?

void Calculator::calculate(Process& P,Results& R)


uint32_t total= P.ProcessRow();

/* Other code to be ignored */



GPIOE->ODR = GPIOE->ODR & ~((uint16_t) ALL_PINS);// turn of All LEDs




LED[1].toggle(); // green LEDs toggling




1 Answer

0 votes
answered Dec 12, 2021 by Peter Minarik (55,660 points)
Yes, it is highly likely that the LEDs turn off and on again quicker than the human eye can react.

You can test it by delaying between the turning off and on again.
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