Intro

This post is about Timer/Counter and Interrupt of Arduino for accurate time control. If you are working on time sensitive project, Timer and Interruput would be better than delay() function.

I used Arduino UNO R3. But I explained the whole process in general from finding MCU model.

💍Find Datasheet

To use timer and interrupt, you should access to the register of MCU. We need datasheet of our MCU.

🙄What's my MCU model?

MCU of UNO R3 is ATMega328P. Memory of timer and interrupt differs by MCU models. Find yours if you use different model.

🙄Find datasheet of your MCU

Now find datasheet of MCU.
FIND DOCS ON OFFICIAL WEBSITE ALWAYS!!

In ATMEL site, I searched ATMega328P.
This is what I used.

💍Timer/Counter

Searching "Timer/Counter", my MCU has two 8-bit timers and one 16-bit timer. What's the difference? Choose appropriate one for considering formula below.

🙄Choose Parameters for 20Hz Output

params

$f_{OCnx}$: Output Frequency You Want (Hz)
$F_{clk\_{I/O}}$: Clock Frequency of Timer/Counter (32MHz for ATMega328P)
$N$: Prescaler
$OCRnx$: Top Value (to find!)

Top이 그 머야.. bit 수 머시기

In my case, it was for external trigger of multi camera time sync.

cont.....