pymp305 0.1.0

Python driver for the ISDT MP305 (MP305A/MP305B) smart bench power supply over USB-HID

pymp305

A pure-Python driver for the ISDT MP305 smart bench power supplies (MP305A and MP305B), talking to it over USB-HID — the same transport the official WebLink web app uses. Reverse-engineered from WebLink's public source-maps; the full protocol is documented in ../PROTOCOL.md. (The recovered upstream JS used during RE is ISDT's copyright and is kept locally under reversing/, which is git-ignored and not published.)

Status: written from the recovered firmware protocol but not yet validated against real hardware (the device hasn't arrived). The framing layer is covered by golden-vector tests (tests/test_protocol.py, all passing). See Bring-up below for first-run checks.

Install

pip install hidapi          # the only runtime dependency
pip install -e .            # from this directory

On Linux you'll need permission to access the hidraw node. Either run as root for a quick test, or add a udev rule (recommended):

# /etc/udev/rules.d/99-pymp305.rules
SUBSYSTEM=="hidraw", ATTRS{idVendor}=="28e9", MODE="0660", TAG+="uaccess"

then sudo udevadm control --reload && sudo udevadm trigger and replug.

Quick start

from pymp305 import MP305

with MP305.open() as psu:
    print(psu.hardware_info())            # name, hw/boot/app versions

    psu.set_output(voltage=5.0, current=1.0, on=True)   # takes remote control + enables output

    st = psu.read_state()
    print(f"{st.voltage:.2f} V  {st.current:.3f} A  {st.power:.2f} W  {st.temperature} C")

    psu.output_off()
    psu.release_remote()                  # hand control back to the front panel

See examples/basic.py for a live-streaming example.

API surface

Method	Does
MP305.list_devices()	enumerate VID 0x28E9 HID interfaces
MP305.open(path=None)	open (auto-picks usage_page 0x01 / usage 0x04)
hardware_info()	0xE0→0xE1 device id, firmware versions
read_state(realtime=True)	0xBD/0xC2→0xC3 live V/I/W/Wh/temp/output (State)
read_system_settings()	0xC4→0xC5 (SystemSettings)
set_output(voltage, current, on, model=0)	take control + apply, returns fresh State
output_on() / output_off()	toggle output
release_remote()	remoteCon=0 — return control to the panel
control(ControlCommand)	low-level 0xC8
set_system_settings(SystemSetCommand)	0xC6
charge(ChargeCommand)	0xEE battery-charge mode
set_language(i)	0xA2
reboot() / enter_bootloader()	danger zone
send(cmd, payload) / request(cmd, expect, payload) / read_frame()	raw access for PDO / programmable / OTA commands not yet wrapped

Units are converted for you: voltage/set_voltage in V, current/set_current in A, power in W, energy in Wh, temperature in °C, working_time in s.

Bring-up checklist (first run with hardware)

1. python -c "from pymp305 import MP305; print(MP305.list_devices())" — confirm the device shows up under VID 0x28E9 and note its usage_page/usage.
2. psu.hardware_info() — if the de-stuffed name/version look right, framing is correct.
3. If reads time out: the device may not use a fixed 64-byte report. Try MP305(dev, report_size=N) with other sizes, or pass an explicit interface path.
4. read_state() polls with the realtime command (0xBD) like the app; if that yields nothing, try read_state(realtime=False) (0xC2).

Tests

python tests/test_protocol.py        # or: pytest

These validate the framing/checksum/stuffing and unit decoding without hardware.

BLE (not implemented here)

The MP305 also speaks the same command set over BLE (used by the PolyLink phone app): GATT service 0000af00-…, characteristic af01 for command/notify, af02 for the binding handshake and chunked writes, plus fee0/fee1 for OTA. BLE frames drop the length/0xAA/checksum wrapper and are just [0x12, cmd, …payload]. Wrapping that with bleak would reuse responses.py directly — left as a future addition.