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How accurate is the timing?

A project log for The VLT - Video Latency Tester

The VLT is a tool to measure how long it takes (in milliseconds) for a video signal to change from one state to another.

nathan-danielsNathan Daniels 09/26/2017 at 01:180 Comments

The question needs to be asked… How long does the Arduino chip take to execute it’s instructions, and do we need a timer to test The VLT timer?! The VLT can be considered obsolete if it is found that the Arduino chip runs too slow. There is obviously no need to test the speed of Video Latency if the testing device introduces it’s own timing issues. The good news is that the analogRead() Arduino function is very quick. According to:

https://www.arduino.cc/en/Reference/AnalogRead

“It takes about 100 microseconds (0.0001 s) to read an analog input, so the maximum reading rate is about 10,000 times a second.”

100 microseconds is not long considering that The VLT is measuring time in milliseconds. Therefore, in my opinion the speed of the ATmega328P chip is sufficient, as the time it takes to execute the analogRead() instruction in the code is negligible.

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