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How fast is analogRead() on the ESP8266?

An analogRead() call on the ESP8266 takes about 90-100 microseconds.

I tested this experimentally using a Wemos D1 Mini board, PlatformIO and this code:

example.cpp
uint32_t t0 = micros();
for (size_t i = 0; i < 1000; i++)
{
    analogRead(A0);
}
uint32_t t1 = micros();
Serial.print("1000 analogRead() calls took [us]: ");
Serial.println(t1-t0);

Output:

example.txt
1000 analogRead() calls took [us]: 97168

Since 1000 analogRead() calls (including some overhead from the loop) took 97.168ms, one analogRead() call takes about 97.168us (+-0.02us).

Check out similar posts by category: Arduino, Electronics, ESP8266/ESP32, PlatformIO