Build your own XLAT

Build Your Own XLAT: A Step-by-Step Guide

The XLAT Mouse Latency Measurement Tool is a specialized device designed for accurate mouse latency measurement. Finalmouse is planning to make ready-made units in sturdy aluminum enclosure available. However, if you want to go the DIY route, this guide outlines the steps to build your own XLAT using the specified hardware and software.

Software Requirements:

Flashing Software: Either JLink software (after cross-flashing the devboard to a JLink), or ST Link software. We recommend the SEGGER JLink software.

• SEGGER JLink software: https://www.segger.com/downloads/jlink/
• STLink to JLink conversion tool: https://www.segger.com/products/debug-probes/j-link/models/other-j-links/st-link-on-board/
• STLink software: https://www.st.com/en/development-tools/stm32cubeprog.html

Step 1: Acquire the Necessary Hardware

• Purchase the STM32F746G-Disco Devboard from a reputable distributor.
• Obtain a Micro-USB OTG Cable, a Mini-USB Cable, and a 5V USB Power Brick.

Step 2: Prepare the Firmware

• Either build the XLAT firmware from source or download the pre-compiled firmware from the release page.

Step 3: Flash the Firmware

• If using JLink software:

  • First, cross-flash the devboard to a JLink using appropriate software.
  • Connect the devboard to your computer.
  • Launch the JLink software: "J-Link Commander"
  • Load the XLAT firmware and flash it to the board:

    connect
    [fill in STM32F746NG when asked for the device]
    [press S to select SWD]
    [press ENTER to confirm the default speed of 4000]
    loadfile path/to/xlat.elf
    r
    g
    q
    

• If using ST Link software:

  • Connect the devboard to your computer.
  • Launch the ST Link software.
  • Load the XLAT firmware and flash it to the board.

Step 4: Hardware Modification

• Place a 2.54 mm pinheader on the CN7 connector of the devboard.

• Solder wires to:

  • CN7 pin 7 -> GND / GROUND
  • CN7 pin 5 -> INPUT / BUTTON

• Short CN7 pin 5 and CN7 pin 4 together by soldering a wire or a solder bridge between them.

• It's advised to isolate the solderpoints with some heatshrink.

• It's also a good idea to make mechanical stress-relief point e.g. by using a tie-wrap and the composite RCA connector on the PCB (see images below)

Here's a close-up of CN7:

Here's an overview of what the board should look like:

Step 5: Identify the Pins

• Pin 7 is the GND (Ground) pin.
• Pin 5 is the INPUT pin.

Step 6: Power Up and Test

• Connect the mini-USB cable to the XLAT device and the USB power brick to power up the device.
• Follow the original XLAT manual for setup and usage instructions to ensure everything is functioning correctly.

Now your self-built XLAT is ready for use!