Auto Power-On¶

The Auto Power-On feature allows the LattePanda to start up automatically without pressing the physical power button.

The LattePanda Iota's auto-power-on configuration differs from previous LattePanda boards: it is set directly via DIP switches and requires no BIOS adjustments, making it simple and convenient.

Naturally, the auto power-on function also can be achieved through the onboard MCU, offering enhanced flexibility.

Configure Auto Power-On via DIP Switch¶

Locate the DIP switch. It is positioned to the left of the RTC battery connector.
The actuator controlling auto power-on is in the upper half of the DIP switch, as highlighted by the red frame in the figure. The "APO" label in the upper-right corner of the DIP switch indicates auto power-on.
Set the actuator:

Position Behavior

OFF (Left Side) Disable the auto power-on function

ON (Right Side) Enable the auto power-on function

Note

Only this actuator of the DIP switch needs to be set; no modifications are required in the BIOS settings!
These settings take effect immediately, and is unaffected by the RTC battery.

Configure Auto Power-On via Onboard MCU¶

GPIO18-21 of the onboard RP2040 MCU are internally connected to pins such as the power button (SW) , run indicator (S0). You can directly program the MCU to perform automatic operations under specific conditions, such as auto power-on.

RP2040 GPIO to Board Control/Indicator Pin Mapping

RP2040 Pin	Board Connection
GPIO18	Internally Connected to S0 State Pin
GPIO19	Internally Connected to S3 State Pin
GPIO20	Internally Connected to SW Button
GPIO21	Internally Connected to RST Button

Indicator Pin Function

	Run	Sleep	Hibernate	Shut Down
S0 State Pin	High	Low	Low	Low
S3 State Pin	Low	High	Low	Low

The following will demonstrate how to use the MCU to achieve auto power-on when external power is supplied.

Referring to the MCU Power Control section, move the actuator on the lower half (marked with "MCU") of the DIP switch to the right side(ON position).

This ensures that the MCU will get power when the LattePanda board is powered, regardless of whether the operating system is booted.
Upload the auto power-on code to the MCU. The Arduino sample code is provided below:

/*
 * LattePanda Iota Auto Power-On via onboard RP2040 MCU
 */
#define PIN_S0 18 // System Status Pin
#define PIN_S3 19 // System Status Pin
#define PIN_SW 20 // Power Button Pin
void setup() 
{
  pinMode(PIN_S0, INPUT); 
  pinMode(PIN_S3, INPUT);
  pinMode(PIN_SW, INPUT); // Initialize SW as INPUT (High Impedance/Floating) to ensure button is released
  delay(1000);  //Wait until power supply is stable
  while( (digitalRead(PIN_S0) == LOW) && (digitalRead(PIN_S3) == LOW) )  // If S0 and S3 are LOW, the system is OFF
  {
    // --- PRESS BUTTON ---
    // Prepare the pin level first, then switch mode to OUTPUT to drive it LOW
    pinMode(PIN_SW, OUTPUT);
    digitalWrite(PIN_SW, LOW); 
    delay(500); // Hold for 500ms
    digitalWrite(PIN_SW, HIGH);
    // --- RELEASE BUTTON ---
    // Switch back to INPUT mode (High Impedance) to simulate release
    pinMode(PIN_SW, INPUT); 
    delay(1000); // Wait 1s before checking S0 and S3 again
  }
}
void loop() 
{
}

After shutting down the LattePanda, disconnect its power supply. Then plug it back in. The LattePanda will automatically power on.

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Position	Behavior
OFF (Left Side)	Disable the auto power-on function
ON (Right Side)	Enable the auto power-on function