sm2can 0.2.0

Open-source macOS/Linux driver for SM2 Pro J2534 CAN adapters

SM2CAN

Open-source macOS/Linux driver for SM2 Pro J2534 CAN adapters (Scanmatik).

The SM2 Pro is a professional automotive diagnostic adapter that officially supports only Windows. SM2CAN provides native macOS and Linux support via clean room reverse engineering of the USB wire protocol.

Install

pip install sm2can

macOS also needs libusb:

brew install libusb

Quick Start

python-can interface

import can

bus = can.Bus(interface='sm2', bitrate=500000)

# Receive
msg = bus.recv(timeout=1.0)
if msg:
    print(f"0x{msg.arbitration_id:03X}: {msg.data.hex()}")

# Send
bus.send(can.Message(arbitration_id=0x7DF,
                     data=[0x02, 0x01, 0x00, 0, 0, 0, 0, 0]))

bus.shutdown()

Direct API

from sm2can import SM2Device

dev = SM2Device()
dev.open(bitrate=500000)

dev.send(0x7DF, bytes([0x02, 0x01, 0x00, 0, 0, 0, 0, 0]))
frame = dev.recv(timeout=1.0)

dev.close()

CLI

sm2can probe              # Detect device, test echo, show firmware info
sm2can info               # Show device info
sm2can monitor            # Live CAN bus monitor
sm2can monitor -l         # Listen-only mode
sm2can send 7DF 0201000000000000   # Send a frame
sm2can echo               # Health check

Protocol

The wire protocol was reverse engineered from the official Scanmatik Android APK and confirmed via live hardware probing.

Frame format:

[CMD, LEN_LO, LEN_HI, CHECKSUM, ...PAYLOAD]

Checksum = (CMD + 0x55 + LEN_HI + LEN_LO) & 0xFF

USB identifiers: VID 0x20A2 PID 0x0001, bulk endpoints 0x02 (OUT) and 0x81 (IN).

See SM2_PRO_PROTOCOL_SPEC.md for the complete protocol specification.

Hardware Requirements

• SM2 Pro adapter (Scanmatik)
• USB cable
• Vehicle connection for CAN bus operations (12V on OBD-II pin 16 powers the vehicle side, but the SM2 Pro itself boots on USB 5V)

Project Status

Component	Status
USB transport (pyusb)	✅ Confirmed
Wire protocol (frame format, checksum)	✅ Confirmed
System commands (INIT, ECHO, DEVICE_INFO, CLEAR_FIFO)	✅ Confirmed
CAN channel commands (0x8A-0x8F)	⏳ Accept payloads, need vehicle bus to verify
python-can integration	✅ Complete
Bluetooth transport	🔧 Framework (needs pybluez)
CLI tools	✅ Complete

Legal

This project uses clean room reverse engineering to achieve interoperability with legitimately purchased hardware. No proprietary code, firmware, or documentation was used. See LEGAL.md for details.

License

MIT — Copyright (c) 2026 Aldo Guzman