Powman – Power Management Library for Micropython

The main goal is to reproduce similar low-power timer and wake-up functionalities in Micropython. It provides direct access to hardware registers through memory-mapped I/O and is intended for bare-metal embedded development.

This project is inspired by and based on the powman library implementation available in the Raspberry Pi Pico SDK

The library directly accesses the RP2350 power management and timer registers via memory-mapped I/O. Official documentation can be found in the RP2350 datasheet, especially in Section 6.0 (Power Management Overview and Section 6.4 (Register Configuration)

It is designed to control low-power modes, timers, and wake-up alarms on Raspberry Pi Pico 2.

Here for tinygo library

Requirements

• Micropython
• Raspberry Pi Pico 2

Usage

Important: powmanGetWakeupReason() must be called before powmanInit(), because init writes to POWMAN registers that may affect wake-up state.

1. Check wake-up reason

import deepsleep

reason = deepsleep.powmanGetWakeupReason()

if reason == 0:
    print("fresh boot")
elif reason & deepsleep.WAKEUP_ALARM:
    print("woke from timer")
elif reason & deepsleep.WAKEUP_GPIO0:
    print("woke from GPIO")

2. Initialize the timer

Set the absolute system time in milliseconds (must be > 0):

deepsleep.powmanInit(1704067200)

3. Enter deep sleep

Sleep for a fixed duration (milliseconds):

deepsleep.powmanOffForMs(10000)  # sleep 10 seconds

Or sleep until a GPIO goes HIGH:

deepsleep.powmanOffUntilGPIO(15)  # wake on GP15 HIGH

Both functions never return — the chip reboots on wake-up.

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Full example

import deepsleep
import time

def main():
    reason = deepsleep.powmanGetWakeupReason()  # before init!

    if reason == 0:
        print("fresh boot")
    elif reason & deepsleep.WAKEUP_ALARM:
        print("woke from timer alarm")
    elif reason & (deepsleep.WAKEUP_GPIO0 | deepsleep.WAKEUP_GPIO1 |
                   deepsleep.WAKEUP_GPIO2 | deepsleep.WAKEUP_GPIO3):
        print("woke from GPIO")

    deepsleep.powmanInit(1704067200)
    deepsleep.powmanOffForMs(5000)

main()

In main.py there is a minimal example`.

Power consumption over one minute.

Results

The consumption during low power mode

How It Works

Powman directly accesses memory-mapped registers to control:

• System timer
• Alarm registers
• Power regulator
• Boot configuration
• Interrupt enable flags

The library uses mem32 internally to read and write hardware registers.

This is required for bare-metal development and is safe in this context.

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API Reference

powmanGetWakeupReason() → int

Returns the reason for the last wake-up as a bitmask. Must be called before powmanInit().

Constant	Value	Meaning
0	0x00	Fresh boot / software reset
WAKEUP_CHIP_RESET	0x01	Chip-level reset
WAKEUP_GPIO0	0x02	Wake from PWRUP0 (used by powmanOffUntilGPIO)
WAKEUP_GPIO1	0x04	Wake from PWRUP1
WAKEUP_GPIO2	0x08	Wake from PWRUP2
WAKEUP_GPIO3	0x10	Wake from PWRUP3
WAKEUP_ALARM	0x40	Wake from timer alarm

The register is a bitmask: multiple bits can be set simultaneously. Use & to test individual sources.

Internally reads CHIP_RESET.HAD_SWCORE_PD (bit 25) to confirm a POWMAN sleep occurred, then reads LAST_SWCORE_PWRUP (offset 0xA0) for the source.

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powmanInit(absTimeMs: int)

Initializes the POWMAN timer with an absolute timestamp in milliseconds (must be > 0).

---

powmanOffForMs(sleepingMs: int)

Enters deep sleep and reboots after sleepingMs milliseconds. Never returns.

---

powmanOffUntilGPIO(gpio: int, high: bool = True)

Enters deep sleep and reboots when the specified GPIO pin reaches the target level. gpio must be 0–49. Never returns.

Parameter	Description
gpio	GPIO pin number (0–49)
high	True = wake on HIGH, False = wake on LOW

Important: The GPIO must already be at the opposite level before calling this function. POWMAN requires a level transition to fire — if the GPIO is already at the wake level when sleep is entered, the chip will never wake.

high	GPIO must be before sleep	Wake trigger
True	LOW	GPIO goes HIGH
False	HIGH	GPIO goes LOW

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Completed

• Timer-based deep sleep (powmanOffForMs)
• GPIO wake-up (powmanOffUntilGPIO)
• Wake-up reason detection (powmanGetWakeupReason)

Future Developments

• Optimize power management by disabling unnecessary components
• Implement a sleep mode that does not reboot the system and preserves the values of variables like machine.lightsleep()

Safety Notes

• Only use in embedded/bare-metal environments.
• Incorrect register values may brick your device.

Supported Platforms

Tested primarily on:

• Raspberry Pi Pico 2