Commu Module

This is the driver library for the module Commu for receiving and sending CAN / RS485 / I2C data.

Support the following products:

UiFlow2 Example

CAN, RS485, I2C communication

Open the commu_core2_example.m5f2 project in UiFlow2.

This example shows how to receive and send data using the Commu Module.

UiFlow2 Code Block:

Example output:

None

MicroPython Example

CAN, RS485, I2C communication

This example shows how to receive and send data using the Commu Module.

MicroPython Code Block:

# SPDX-FileCopyrightText: 2025 M5Stack Technology CO LTD
#
# SPDX-License-Identifier: MIT

import os, sys, io
import M5
from M5 import *
from module import CommuModuleCAN
from module import CommuModuleRS485
from module import CommuModuleI2C
from hardware import Pin


title0 = None
label0 = None
label1 = None
label2 = None
commu_0 = None
commu_1 = None
commu_2 = None


def setup():
    global title0, label0, label1, label2, commu_0, commu_1, commu_2

    M5.begin()
    Widgets.fillScreen(0x222222)
    title0 = Widgets.Title(
        "COMMUModule Core2 Example", 3, 0xFFFFFF, 0x0000FF, Widgets.FONTS.DejaVu18
    )
    label0 = Widgets.Label("CAN Rec:", 1, 77, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label1 = Widgets.Label("RS485 Rec:", 1, 121, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)
    label2 = Widgets.Label("I2C List:", 1, 166, 1.0, 0xFFFFFF, 0x222222, Widgets.FONTS.DejaVu18)

    commu_0 = CommuModuleCAN(0x00, baudrate=16)
    commu_1 = CommuModuleRS485(2, baudrate=115200, bits=8, parity=None, stop=1, tx=14, rx=13)
    commu_2 = CommuModuleI2C(0, scl=Pin(22), sda=Pin(21), freq=100000)


def loop():
    global title0, label0, label1, label2, commu_0, commu_1, commu_2
    M5.update()
    if commu_0.any():
        label0.setText(str((str("CAN Rec:") + str((commu_0.recv())))))
    if BtnA.isPressed():
        commu_0.send("uiflow2", 0, extframe=False)
    elif BtnB.isPressed():
        label2.setText(str((str("I2C List:") + str((commu_2.scan())))))
    if commu_1.any():
        label1.setText(str((str("RS485 Rec:") + str((commu_1.read())))))


if __name__ == "__main__":
    try:
        setup()
        while True:
            loop()
    except (Exception, KeyboardInterrupt) as e:
        try:
            from utility import print_error_msg

            print_error_msg(e)
        except ImportError:
            print("please update to latest firmware")

Example output:

None

API

CommuModule

class module.commu.CommuModuleCAN(mode=0, baudrate=16, spi_baud=8000000, canIDMode=0, debug=False)

Bases: MCP2515_CAN

Create an CommuModuleCAN object

Parameters:

mode (int) –
The CAN mode to use(NORMAL, LISTEN_ONLY), Default is NORMAL.
Options:
- NORMAL: Normal mode
- LISTEN_ONLY: Listen only mode
baudrate (int) –
The baudrate to use, Default is CAN_1000KBPS.
Options:
- CAN_5KBPS: 5Kbps
- CAN_10KBPS: 10Kbps
- CAN_20KBPS: 20Kbps
- CAN_31K25BPS: 31.25Kbps
- CAN_33KBPS: 33Kbps
- CAN_40KBPS: 40Kbps
- CAN_50KBPS: 50Kbps
- CAN_80KBPS: 80Kbps
- CAN_83K3BPS: 83.33Kbps
- CAN_95KBPS: 95Kbps
- CAN_100KBPS: 100Kbps
- CAN_125KBPS: 125Kbps
- CAN_200KBPS: 200Kbps
- CAN_250KBPS: 250Kbps
- CAN_500KBPS: 500Kbps
- CAN_1000KBPS: 1Mbps
spi_baud (int) – The SPI baudrate to use, Default is 8000000.
canIDMode (int) –
The CAN ID mode to use(MCP_STDEXT, MCP_EXTDONLY), Default is MCP_STDEXT.
Options:
- MCP_STDEXT: Standard and Extended
- MCP_EXTDONLY: Extended only
debug (bool) – Whether to enable debug mode, Default is False.

UiFlow2 Code Block:

MicroPython Code Block:

from module import CommuModuleCAN

commu = CommuModuleCAN(CommuModule.NORMAL, baudrate=16)

any()

Check if any message is available.

Returns:: The current message availability.
Return type:: bool

UiFlow2 Code Block:

MicroPython Code Block:

commu.any()

info()

Get the state of error information.

Returns:: The current error information.
Return type:: str

UiFlow2 Code Block:

MicroPython Code Block:

commu.info()

recv(fifo=0, list=None, timeout=5000)

Read a message from the CAN bus.

Parameters:

fifo (int) – The fifo is an integer, it can be any number and compatible with Pyb.CAN
list (list) – list is an optional list object to be used as the return value.
timeout (int) – timeout is the timeout in milliseconds to wait for the receive.

Returns:

Tuple containing (can_id, is_extended, is_rtr, fmi, data)

Return type:

tuple

The id of the message.
A boolean that indicates if the message ID is standard or extended.
A boolean that indicates if the message is an RTR message.
The FMI (Filter Match Index) value.
An array containing the data.

UiFlow2 Code Block:

MicroPython Code Block:

commu.recv(0)

buf = bytearray(8)
lst = [0, 0, 0, 0, memoryview(buf)]
# No heap memory is allocated in the following call
commu.recv(0, lst)

send(data, can_id, extframe=False)

Send a message to the CAN bus.

Parameters:

data (str) – The message data.
can_id (int) – The CAN ID.
extframe (bool) – Whether to use extended frame format.

Returns:

The message data.

Return type:

str

UiFlow2 Code Block:

MicroPython Code Block:

commu.send('uiflow2', 0, extframe=False)

class module.commu.CommuModuleRS485(id, **kwargs)

Bases: object

The CommuModuleRS485 class wraps an instance of the UART class.

For more details, see hardware.UART.

class module.commu.CommuModuleI2C(id, **kwargs)

Bases: object

The CommuModuleI2C class wraps an instance of the I2C class.

For more details, see machine.I2C. – a two-wire serial protocol.