EasyLoader (beta)

Current Product Don't Have Test Firmware

Note: pls, use PC chrome/edge browser, if can't connect, refresh the webpage.

1. Click connect button

2. After connected successfully, pick a firmware

3. Click the burn button

4. After burning successfully, Unplug the device and restart.





ATOM DTU CAT1 is a programmable LTE CAT1 Data Transfer Unit (DTU). Built-in SIM-A7680C module that adapts to LTE CAT1 frequency band in China, supports LTE-TDD/LTE-FDD wireless communication standard. Compared with NBIoT, CAT1 has stronger data transmission capability. The maximum downlink rate can reach 10Mbps (uplink)/5Mbps (downlink). The integrated SMA external antenna interface improves the communication quality and signal stability of the device. Different from the general DTU that only has the function of data transparent transmission, the ATOM DTU series adopts a more open architecture design. The controller ATOM LITE can modify the program at will according to the actual business. The whole machine reserves a variety of interfaces (RS485, I2C, custom interface) for users to expand, which is convenient for the quick access of sensors and actuators. With its own guide rail clamping structure, it is perfectly embedded in various industrial control sites. It is very suitable for application scenarios that require data transmission rate (remote control/data transparent transmission, etc).

Product Features

  • SIM-A7680C
    • Applicable to CAT1 frequency band in China
    • LTE CAT1 module, support LTE-TDD/LTE-FDD wireless communication standard
    • The maximum downlink rate is 10Mbps/the maximum uplink rate is 5Mbps.
    • UART interface/AT command control
    • Card slot specification: MicroSIM
  • Base expansion interface:
    • 1x PWR485(RS485(support Modbus Master/Slave) + DC12V POWER INPUT)
    • 1x I2C
  • ATOM main control expansion interface:
    • 1x full function GPIO
  • Comes with rail clamp
  • Development Platform:


  • 1x ATOM LITE
  • 1x ATOM DTU CAT1
  • 1x SMA Antenna
  • 1x SMA red cap
  • 1x M2 hex key
  • 1x M2x16 screw
  • 1x 3.96-4P terminal


  • Remote Control/Data Acquisition
  • Cloud application of data

SIM-A7680C Module Certification



Specifications Parameters
Communication Module SIM-A7680C
Up and Down Speed ​ Maximum Downlink Rate 10Mbps / Maximum Uplink Rate 5Mbps
Support CAT1 frequency band LTE-TDD: B34/B38/B39/B40/B41
LTE-FDD: B1/B3/B5/B8
Communication UART 115200bps 8N1
RS485 IC SP3485EN-L/TR
Input voltage ATOM LITE (DC 5V), RS485 side input (DC 12V)
Net Weight 32g
Gross Weight 47g
Product size 64 * 24 * 29mm
Packing Size 91 * 42 * 24.5mm

Pin mapping

  • SIM-A7680C
  • RS485
  • I2C






Q1: How do I remove the speaker floor noise when the M5Core is on or running?

Execute the following statement in Setup() of the Arduino program

Q2: How does M5Core2 stack modules?

When M5Core2 is stacked with other M5 modules, you need to remove the battery base of Core2, which does not support module stacking.

Q3: A timeout error is displayed when uploading the program to the device

Reason and solution: The power supply current of the port is insufficient, which can cause the device to not enter the download mode normally. You can try to connect a capacitor (>0.1uF) between the RST pin and the GND pin, or when uploading the program, set the G0 Short-circuit to GND, so that G0 can be set to a low level state normally

Q4: How to solve the phenomenon of automatic signal triggering of M5Core button A

Add the header file #include <driver/adc.h> and the function adc_power_acquire(); in the Arduino program

Q5: M5 device battery life

The battery life of the controller is affected by various factors such as battery capacity, operating status, and load, so there is no fixed value. Reducing the load and adopting a sleep strategy can effectively increase the battery life.

Q6: Can multiple modules with batteries be stacked at the same time?

Support multiple stacks, the total capacity of the batteries in parallel increases, and the voltage remains unchanged. However, since the discharge of each battery is not balanced during use, there is a voltage difference between the batteries, which may cause the battery to charge backwards. .(will lose part of the battery capacity)

Q7: M5 master supports WiFi connection to 5G frequency band

ESP32 module currently does not support WiFi in 5G band, only 2.4G.

Q8: The RS485 device cannot communicate normally/data is garbled. Packet loss, etc.

Confirm whether the TX/RX pin on the TTL side of the pin is correct, try to add two 120Ω terminal resistors at the beginning and end of the device line to reduce signal reflection interference

Q9: The difference between different masters and camera products

Click the link below to view the product comparison table

Q10: M5 camera image blur, how to adjust the focal length

Rotate the lens to adjust the focal length within a certain range

Q1: How to read the programmed firmware?

Use esptool to read the flash content of esp32 and export the bin file. Refer to the detailed operation

Q2: Several solutions for esp32 board download failure in Arduino IDE board management

Restart the Arduino IDE, the computer uses the mobile AP mobile network to download.

Method 3: Download the resource package provided by M5Stack for direct installation, and extract the contents to the board management path of Arduino, such as (C:\Users\Sean\AppData\Local\Arduino15\packages), https://m5stack.oss-cn-shenzhen.aliyuncs.com/resource/arduino/packages/m5stack_v2.0.0.zip
Q3: Arduino SPIFFS file upload operation

Refer to the Github link below, use arduino-esp32fs-plugin for file upload

Q4: When M5Burner burns firmware, an error pop-up window or exception occurs

Check if the COM of the corresponding device is selected and if the M5Burner is the latest version

Q5: Does the M5 master device support multi-language display (Chinese, English, Japanese, Russian, etc.)?

UIFlow users can switch the Label font to Unicode, Arduino users can use the Chinese font library provided in the M5GFX driver library

Q6: The program cannot load the SD card normally

Confirm whether the SD card format is FAT32, and no partitions exist.

Q7: How to use Bluetooth, HTTP, SD, WebServer, FreeRTOS and other features in Arduino IDE

You can refer to the following link for other ESP32 users to share the case program

Q8: How to download programs for STAMP C3U

STAMP C3U enters program download mode operation: 1. Long press the center button (G9) of STAMP C3U when the power is off. 2. Connect to the computer, after the port is successfully identified, program burning.

Q9: How STAMP C3U defines UART0 output mode

By default, USB CDC is not enabled, the serial port output started by C3U will be output through the default pins (G20, G21) of UART0. If you want to output through USB, please use the IDE to output Its USB CDC option is enabled. (Arduino users can enable it through Tools->USB CDC on Boot-Enabled. For IDF users, please refer to the ESP IDF official documentation.)

Q10: Unable to connect to UIFlow Desktop IDE

Refer to the UIFlow documentation of the corresponding device to check whether the device has entered the USB programming mode.


Q1: Consultation for after-sales problems of products

Describe the problems encountered in detail. Screenshots of the programs involved or files can be added as attachments and sent to M5Stack's official after-sales email

Q2: Code Resources, Cases, User Communication