What is the default PlatformIO / Arduino ESP32 CPU clock frequency?

On PlatformIO / Arduino, by default the ESP32 clock frequency is 80 MHz (the default 240 MHzCPU frequency divided by 4)

If you want to verify this yourself, use this firmware:

esp32_timer_base_clk_example.cpp

#include <Arduino.h>

void setup() {
    Serial.begin(115200);
    Serial.println(TIMER_BASE_CLK);
}

void loop() {
}

#include <Arduino.h>

void setup() {
    Serial.begin(115200);
    Serial.println(TIMER_BASE_CLK);
}

void loop() {
}

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