pymp305 0.4.8

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) over USB-HID (sync) and Bluetooth (async) — the same protocol the official WebLink web app and PolyLink phone app use. Reverse-engineered from WebLink's public source-maps; the full protocol is documented in ../PROTOCOL.md. (The recovered upstream JS is ISDT's copyright and is kept locally under reversing/, which is git-ignored and not published.)

Status: not yet validated against real hardware. Framing, decoding, units, and firmware-decrypt are covered by golden-vector tests (pytest, all passing), but nothing here has talked to a device — open() emits a one-time UserWarning to that effect, and OTA flashing is gated behind an explicit allow_untested_ota=True. See Bring-up below.

Install

pip install pymp305          # USB-HID (pulls in hidapi)
pip install pymp305[ble]     # + Bluetooth transport (bleak)

From source (development): pip install -e . from this directory.

A Dracula-themed PyQt6 desktop GUI (live charts + simulator) lives in ../gui.

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
set_language(i)	0xA2
read_charge_state() / read_charge_settings()	0xEC→0xED / 0xEA→0xEB (ChargeState / ChargeInfo)
charge(ChargeCommand)	0xEE start/stop a battery charge
read_pdo(id) / pdo_connect(PDOConnect) / write_pdo(...)	0xD0→0xD1 read / 0xE8→0xE9 select / 0xD2→0xD3 define a PD profile
read_program_list() / read_program_steps(id, n)	0xD4→0xD5 / 0xD8→0xD9
read_program_state() / program_connect(ProgramConnect)	0xDE→0xDF / 0xE2→0xE3 run a sequence
write_program(id, steps) / program_change(...)	0xDA→0xDB write steps / 0xD6→0xD7 create/rename/delete slot
read_emarker()	USB-C cable e-marker info (speed/format labelled)
flash(Firmware, allow_untested_ota=True)	experimental OTA over HID (see warnings)
reboot() / enter_bootloader()	danger zone
send(cmd, payload) / request(cmd, expect, payload) / read_frame()	raw access for any other command

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.

Transports

• MP305 — synchronous, USB-HID (this table).
• MP305BLE — the same API but async over Bluetooth (bleak); methods are coroutines and connection is await MP305BLE.open(). Adds flash_ble(IntelHexFirmware, allow_untested_ota=True) (experimental BLE OTA over fee0/fee1). See examples/ble.py.

Firmware (pymp305.ota)

• Firmware.parse(bytes) — decrypt + verify an official .bin (key is in the header).
• IntelHexFirmware.parse(...) — the BLE FEE1 firmware format.
• tools/fetch_firmware.py downloads + decrypts official images into git-ignored reversing/.
• OTA writing is experimental and untested on hardware — see the repo banner.

Experimental / undisclosed commands

Reverse-engineered from the firmware (handled by the device but never sent by the official app). Untested on hardware — see notes in reversing/FINDINGS-commands.md.

• get_language() — read the UI language index (cmd 0xA0→0xA1), the read counterpart of set_language(). Read-only; the safe first probe.
• soft_reset(confirm=True) — magic-gated (0xFE AA 55) soft re-init of the regulator/ USB-PD state to defaults + control-task restart. Static analysis shows no flash/NVM access (can't brick), but it resets the live output, so it's gated behind confirm=True.

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

pytest                 # runs all suites (framing, charge/PD/program, OTA, experimental)

All run without hardware — they validate framing/checksum/stuffing, unit decoding, the firmware decryptor, and the command builders against golden vectors.

BLE transport

Implemented via MP305BLE (async, bleak) — see Transports above and examples/ble.py. Over BLE the same command set is used but frames drop the length/0xAA/checksum wrapper ([0x12, cmd, …payload]): commands go to GATT characteristic af01, responses arrive as notifications (parsed at index 2, reusing responses.py), and an af02 binding handshake starts the session; fee0/fee1 carry BLE OTA.

MP305 has Bluetooth, but its BLE-module firmware isn't published in the OTA feed and this transport is unverified on hardware — USB-HID is the primary path.