Quelltext der Seite WSAL23452 – Power Management HAT (B)/en

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'''Documentation notice:''' This technical documentation was independently rewritten from an archived supplier source. Check technical details and commands against the product version and manufacturer documentation before use.

== Summary ==
The Power Management HAT (B) is a power-management add-on for Raspberry Pi. It provides timed power on/off, voltage and current monitoring, an embedded RTC chip, and multiple protection circuits.

== Related products at JW Tech ==
* [https://shop.jw-tech.eu/p/WSAL23452 WSAL23452 – Power Management HAT for Raspberry Pi, Supports charging And Power output at the same time, Embedded RTC and Multiple Protection Circuits]

== Technical overview ==
* Board size: 56.5 mm × 65 mm; mounting hole diameter 3.0 mm.
* Main processor: RP2040; communication via UART + GPIO; default baud rate 115200 bps (configurable).
* Input power: USB at 5 V or PH2.0 connector at 3.3–4.2 V (typically a 3.7 V Li battery, not included).
* Built-in protections: battery reverse-polarity guard, counter-current guard, and real-time voltage/current monitoring.
* GPIO connections: UART0_TX/RX to RPI D15/D14; I2C1 SDA/SCL to II2 SDA/SCL; user key on GPIO19; soft-shutdown pin to RPI D20; run-state pin to RPI D21; power-control pin (low = off); status LED; input-voltage divider (about 1/10 of input voltage).
* Demo modes: Button_Ctr (toggle power with the PWR button), Period_Time (default 9:00:30 on / 10:00:00 off), Cycle_Time (1800 s on / 3600 s off).
* Programming via SWD (OpenOCD) or USB (UF2 bootloader): press Reset and BOOT, release Reset first then BOOT, drag-and-drop the .elf into the mass-storage device.
* While programming, power the board through the Raspberry Pi’s power port because flashing resets the RP2040 and interrupts power.
* The soft-shutdown script requires a Raspberry Pi reboot to take effect; without rebooting, the configuration will not apply.
* Theoretical maximum output current is 3 A; with a fully charged 3.7 V Li battery, the practical limit is about 2 A.

'''Commands and examples – verify before use:''' 
<syntaxhighlight lang="text">
sudo raspi-config
sudo minicom -D /dev/ttyS0
openocd -f interface/raspberrypi-swd.cfg -f target/rp2040.cfg -c "program ./Power_Management_HAT.elf verify reset exit"
</syntaxhighlight>

== Notes and version constraints ==
* Li-ion and Li-po batteries can cause fire, personal injury, or property damage if mishandled; never connect them in reverse polarity, avoid inferior chargers, and do not mix old and new cells.
* Battery cycle life is limited; replace when max cycles are reached or after two years of service, whichever comes first.
* Programming over SWD resets the RP2040 and interrupts power supply—during this time, power the Raspberry Pi through its own power port.
* The OpenOCD build is version-sensitive (branch rp2040-v0.12.0); differences in SDK or driver versions may cause failures.
* Demo timing values are defaults and should be adjusted to the intended use before deployment.
* When using a Li battery, confirm that the battery specification matches the board and that the cell has been aged and tested by the manufacturer.

== Source and revision record ==
* [https://www.waveshare.com/wiki/Power_Management_HAT_(B) Power Management HAT (B) - Waveshare Wiki]
* Source revision: 73958
* Captured: 2026-09-04T03:00:43+00:00
* SHA-256: <code>5e3466193f6ccdf7d8ef3a99531e1e23d9ceb2113c42ad74f8dbe1c07960d738</code>