ATORCH J7-c

The ATORCH J7-c is a USB load meter which can measure various properties for USB devices including their voltage, current, power, resistance, capacity, temperature, data line voltage, and charging mode. Communicates to the host by means of serial over bluetooth.

ATORCH J7-c

Status	supported
Source code	[1]
Connectivity	serial over Bluetooth, BLE
Measurements	voltage, current, power, energy, voltage over USB data lines
Features	measures USB devices; color display
Website	en.atorch.cn

Hardware

It features the following connectors :

• USB-A male ( USB 2.0 only )
• USB-A female ( USB 2.0 only)
• USB-C male
• USB-C female
• USB-microB female

A CH573F MCU is responsible for performing all the measurements and managing the user interface.

A small SOIC-8 IC (marking BP0D608-68A2) handles the Bluetooth communication (both RFCOMM and BLE). Might be AC6328B

Pictures

• 

  Top side of the board

• 

  Bottom side of the board

Protocol

The device communicates through serial-over-Bluetooth (RFCOMM), appearing under the UC96_SPP name, and BLE, under the UC96_BLE name. The same protocol is used both on the BLE and Bluetooth link.

The manufacturer provides an app named "E_Test" for Android and iOS, but no protocol documentation, although it appears that the protocol has been fully reverse-engineered [2].

The RFCOMM transport uses channel number 2. The BLE transport can be made to work using the following parameters : handle_rx = 0x000C, handle_tx = 0x000F, handle_cccd = 0x000D, value_cccd = 0x0001

Links

• vendor software in the Aliexpress store
• github syssi esphome-atorch-dl24 protocol-design text document