PyMCU Libraries

Architectural Shift: MicroPython Compatibility

PyMCU’s standard library is being restructured. The official user-facing API will soon be aligned with the MicroPython / CircuitPython machine and board modules.

The modules documented below (pymcu.hal.* and pymcu.drivers.*) are considered internal foundations (HAL). While they work perfectly, they are designed to be wrapped by the upcoming compatibility layers. Users are strongly encouraged to use the machine module (when available) for better portability across different hardware.

The PyMCU internal library provides hardware abstraction layer (HAL) modules and device drivers. All modules compile to tight native machine code — there is no Python runtime on the device.

Internal HAL modules

Module	Import path	Description
GPIO / Pin	pymcu.hal.gpio	Digital I/O, pin interrupts
UART	pymcu.hal.uart	Serial communication
ADC	pymcu.hal.adc	Analog-to-digital conversion
Timer	pymcu.hal.timer	Hardware timers
PWM	pymcu.hal.pwm	Pulse-width modulation
SPI	pymcu.hal.spi	SPI bus (hardware + soft)
I2C	pymcu.hal.i2c	I2C bus (hardware + soft)
EEPROM	pymcu.hal.eeprom	Non-volatile byte storage
Watchdog	pymcu.hal.watchdog	Watchdog timer
Power / Sleep	pymcu.hal.power	Sleep modes
Time / Delays	pymcu.time	Busy-wait delays

Device drivers

Driver	Import path	Description
DHT11	pymcu.drivers.dht11	Temperature and humidity sensor

Design principles

All HAL classes are @inline — they have zero SRAM cost. Instantiating a Pin or UART compiles to register writes; no struct is allocated on the MCU. See Type System for details on the Zero-Cost Abstraction model.