Maximum frequency an Arduino can generate

September 7, 2015 · Admin Arduino

What is the maximum frequency an Arduino can generate? Typically, I obtained a frequency of less than 100 kHz using the Arduino function calls. The results were lower than I expected. I also observed that I had a frequency higher by 25 kHz using a pin from the 8 to 13 pin set than a pin from the 0 to 7 pin set. These tests yield a virtually perfect waveform. I obtained almost 4 MHz by accessing the register directly. The waveform was not as good as the waveform of the first four tests. The waveform is given in Figure 1.


Sketch 1	Frequency: 72.6 kHz Duty Cycle: 47.7%	`#include #define OUTPUT_PIN 3 void setup() { pinMode(OUTPUT_PIN, OUTPUT); } void loop() { digitalWrite(OUTPUT_PIN, HIGH); digitalWrite(OUTPUT_PIN, LOW); }`
Sketch 2	Frequency: 74.3 kHz Duty Cycle: 49.2%	`#include #define OUTPUT_PIN 3 void setup() { pinMode(OUTPUT_PIN, OUTPUT); } void loop() { while(1) { digitalWrite(OUTPUT_PIN, HIGH); digitalWrite(OUTPUT_PIN, LOW); } }`
Sketch 3	Frequency: 96.94 kHz Duty Cycle: 49%	`#include #define OUTPUT_PIN 8 void setup() { pinMode(OUTPUT_PIN, OUTPUT); } void loop() { digitalWrite(OUTPUT_PIN, HIGH); digitalWrite(OUTPUT_PIN, LOW); }`
Sketch 4	Frequency: 96.94 kHz Duty Cycle: 49%	`#include #define OUTPUT_PIN 8 void setup() { pinMode(OUTPUT_PIN, OUTPUT); } void loop() { while(1) { digitalWrite(OUTPUT_PIN, HIGH); digitalWrite(OUTPUT_PIN, LOW); } }`
Sketch 5	Frequency: 3.97 MHz Duty Cycle: 25.6%	`#include void setup() { DDRB = B00000001; } void loop() { while(1) { PORTB = 0xff; PORTB = 0x00; } }`

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Figure 1: Waveform generated by modifying directly the port (Sketch 5)