microcontroller – Pin references and cpu functionality

The microcontroller module defines the pins from the perspective of the microcontroller. See board for board-specific pin mappings.

microcontroller.cpu :Processor

CPU information and control, such as cpu.temperature and cpu.frequency (clock frequency). This object is an instance of microcontroller.Processor.

microcontroller.cpus :Processor

CPU information and control, such as cpus[0].temperature and cpus[1].frequency (clock frequency) on chips with more than 1 cpu. The index selects which cpu. This object is an instance of microcontroller.Processor.

microcontroller.delay_us(delay: int)None

Dedicated delay method used for very short delays. Do not do long delays because this stops all other functions from completing. Think of this as an empty while loop that runs for the specified (delay) time. If you have other code or peripherals (e.g audio recording) that require specific timing or processing while you are waiting, explore a different avenue such as using time.sleep().


Disable all interrupts. Be very careful, this can stall everything.


Enable the interrupts that were enabled at the last disable.

microcontroller.on_next_reset(run_mode: RunMode)None

Configure the run mode used the next time the microcontroller is reset but not powered down.


run_mode (RunMode) – The next run mode


Reset the microcontroller. After reset, the microcontroller will enter the run mode last set by on_next_reset.


This may result in file system corruption when connected to a host computer. Be very careful when calling this! Make sure the device “Safely removed” on Windows or “ejected” on Mac OSX and Linux.

microcontroller.nvm :Optional[nvm.ByteArray]

Available non-volatile memory. This object is the sole instance of nvm.ByteArray when available or None otherwise.


nvm.ByteArray or None

microcontroller.watchdog :Optional[watchdog.WatchDogTimer]

Available watchdog timer. This object is the sole instance of watchdog.WatchDogTimer when available or None otherwise.

class microcontroller.Pin

Identifies an IO pin on the microcontroller.

Identifies an IO pin on the microcontroller. They are fixed by the hardware so they cannot be constructed on demand. Instead, use board or microcontroller.pin to reference the desired pin.

class microcontroller.Processor

Microcontroller CPU information and control


import microcontroller

Note that on chips with more than one cpu (such as the RP2040)
microcontroller.cpu will return the value for CPU 0.
To get values from other CPUs use microcontroller.cpus indexed by
the number of the desired cpu. i.e.


You cannot create an instance of microcontroller.Processor. Use microcontroller.cpu to access the sole instance available.

frequency :int

The CPU operating frequency in Hertz. (read-only)

reset_reason :ResetReason

The reason the microcontroller started up from reset state.

temperature :Optional[float]

The on-chip temperature, in Celsius, as a float. (read-only)

Is None if the temperature is not available.

uid :bytearray

The unique id (aka serial number) of the chip as a bytearray. (read-only)

voltage :Optional[float]

The input voltage to the microcontroller, as a float. (read-only)

Is None if the voltage is not available.

class microcontroller.ResetReason

The reason the microntroller was last reset

POWER_ON :object

The microntroller was started from power off.

BROWNOUT :object

The microntroller was reset due to too low a voltage.

SOFTWARE :object

The microntroller was reset from software.


The microntroller was reset for deep sleep and restarted by an alarm.

RESET_PIN :object

The microntroller was reset by a signal on its reset pin. The pin might be connected to a reset button.

WATCHDOG :object

The microcontroller was reset by its watchdog timer.

UNKNOWN :object

The microntroller restarted for an unknown reason.

class microcontroller.RunMode

run state of the microcontroller

Enum-like class to define the run mode of the microcontroller and CircuitPython.


Run CircuitPython as normal.


Run CircuitPython in safe mode. User code will not be run and the file system will be writeable over USB.


Run the bootloader.