#!/usr/bin/env python3 """ I2C Doctor — USB/I2C Bridge host script. Requires: pip install pyserial Usage (interactive CLI): python3 bridge.py --port /dev/tty.usbserial-* [--baud 115200] Usage (as library): from bridge import I2CBridge with I2CBridge('/dev/tty.usbserial-0001') as b: print(b.scan()) data = b.read_reg(0x48, 0x00, 2) b.write_reg(0x48, 0x01, bytes([0x60])) Protocol (ASCII, newline-terminated): SCAN -> OK:3C 48\r\n (space-separated hex addresses, empty if none) PROBE XX -> OK\r\n / ERR:NACK\r\n READ XX N -> OK:AA BB\r\n (addr hex, count decimal — no register) READ XX XX N -> OK:AA BB\r\n (addr hex, reg hex, count decimal) WRITE XX YY.. -> OK\r\n (addr hex, data hex bytes — no register) READ_REG XX XX N -> OK:AA BB\r\n (addr hex, reg hex, count decimal) WRITE_REG XX XX YY.. -> OK\r\n (addr hex, reg hex, data hex bytes) SPEED N -> OK\r\n (speed decimal) """ import argparse import time import serial class I2CBridge: """USB to I2C bridge for the I2C Doctor device.""" def __init__(self, port: str, baud: int = 115200, timeout: float = 5.0): self.ser = serial.Serial(port, baud, timeout=timeout) time.sleep(0.2) self.ser.reset_input_buffer() def _cmd(self, cmd: str) -> str: self.ser.reset_input_buffer() self.ser.write((cmd + '\n').encode()) resp = self.ser.readline().decode(errors='replace').strip() return resp def scan(self) -> list: """Scan the I2C bus. Returns list of found 7-bit addresses (int).""" resp = self._cmd('SCAN') if not resp.startswith('OK:'): raise IOError(f'SCAN failed: {resp!r}') part = resp[3:].strip() return [int(x, 16) for x in part.split()] if part else [] def probe(self, addr: int) -> bool: """Probe address `addr` (7-bit int). Returns True if ACK received.""" resp = self._cmd(f'PROBE {addr:02X}') return resp == 'OK' def read(self, addr: int, length: int) -> bytes: """Read `length` bytes from device at `addr` (7-bit) without register address.""" resp = self._cmd(f'READ {addr:02X} {length}') if not resp.startswith('OK:'): raise IOError(f'READ 0x{addr:02X} failed: {resp!r}') return bytes(int(x, 16) for x in resp[3:].split()) def write(self, addr: int, data: bytes) -> None: """Write `data` to device at `addr` (7-bit) without register address.""" hex_bytes = ' '.join(f'{b:02X}' for b in data) resp = self._cmd(f'WRITE {addr:02X} {hex_bytes}') if resp != 'OK': raise IOError(f'WRITE 0x{addr:02X} failed: {resp!r}') def read_reg(self, addr: int, reg: int, length: int) -> bytes: """Read `length` bytes from register `reg` of device at `addr` (7-bit).""" resp = self._cmd(f'READ_REG {addr:02X} {reg:02X} {length}') if not resp.startswith('OK:'): raise IOError(f'READ_REG 0x{addr:02X} reg 0x{reg:02X} failed: {resp!r}') return bytes(int(x, 16) for x in resp[3:].split()) def write_reg(self, addr: int, reg: int, data: bytes) -> None: """Write `data` to register `reg` of device at `addr` (7-bit).""" hex_bytes = ' '.join(f'{b:02X}' for b in data) resp = self._cmd(f'WRITE_REG {addr:02X} {reg:02X} {hex_bytes}') if resp != 'OK': raise IOError(f'WRITE_REG 0x{addr:02X} reg 0x{reg:02X} failed: {resp!r}') def speed(self, speed: int): """Set I2C speed.""" resp = self._cmd(f'SPEED {speed}') return resp == 'OK' def close(self) -> None: self.ser.close() def __enter__(self): return self def __exit__(self, *_): self.close() def _interactive(bridge: I2CBridge) -> None: try: import readline # enables arrow-key history on macOS/Linux readline.set_history_length(100) except ImportError: pass print("I2C Doctor Bridge — ready. Commands: scan, probe, read, write, read_reg, write_reg, help, quit") while True: try: line = input('i2c> ').strip() except (EOFError, KeyboardInterrupt): print() break if not line: continue parts = line.split() cmd = parts[0].lower() try: if cmd in ('quit', 'exit', 'q'): break elif cmd == 'help': print(' scan scan bus, list found addresses') print(' probe check if address ACKs') print(' read read n bytes (no register addr)') print(' read read n bytes from register') print(' read_reg read n bytes from register') print(' write <..> write bytes (no register addr)') print(' write_reg <..> write bytes to register') print(' speed speed in kbit/s (10, 50, 100, 200, 400, 1000)') elif cmd == 'scan': addrs = bridge.scan() if addrs: print('Found:', ', '.join(f'0x{a:02X}' for a in addrs)) else: print('No devices found') elif cmd == 'probe' and len(parts) == 2: print('ACK' if bridge.probe(int(parts[1], 16)) else 'NACK') elif cmd == 'read' and len(parts) == 4: data = bridge.read_reg(int(parts[1], 16), int(parts[2], 16), int(parts[3])) print(' '.join(f'{b:02X}' for b in data)) elif cmd == 'read' and len(parts) == 3: data = bridge.read(int(parts[1], 16), int(parts[2])) print(' '.join(f'{b:02X}' for b in data)) elif cmd == 'read_reg' and len(parts) == 4: data = bridge.read_reg(int(parts[1], 16), int(parts[2], 16), int(parts[3])) print(' '.join(f'{b:02X}' for b in data)) elif cmd == 'write' and len(parts) >= 3: bridge.write(int(parts[1], 16), bytes(int(x, 16) for x in parts[2:])) print('OK') elif cmd == 'write_reg' and len(parts) >= 4: bridge.write_reg(int(parts[1], 16), int(parts[2], 16), bytes(int(x, 16) for x in parts[3:])) print('OK') elif cmd == 'speed' and len(parts) == 2: bridge.speed(int(parts[1], 10)) print('OK') else: print(f"Unknown or malformed command: '{line}'. Type 'help'.") except (IOError, ValueError) as e: print(f'Error: {e}') def main() -> None: parser = argparse.ArgumentParser(description='I2C Doctor USB Bridge') parser.add_argument('--port', required=True, help='Serial port (e.g. /dev/tty.usbserial-*, /dev/ttyUSB0, COM3)') parser.add_argument('--baud', type=int, default=115200, help='Baud rate (default: 115200)') args = parser.parse_args() with I2CBridge(args.port, args.baud) as bridge: _interactive(bridge) if __name__ == '__main__': main()