3a (tr)uSDX Bootloader

The Bootloader should be burnt onto the devices by the Group Buy Organizer. In this case, the end user doesn´t need a deticated programmer. But in the unfortunate case your Group Buy Organizer didn´t burn the Bootloader for you or you´ve built it on your own, or something went wrong, or you just want to do it yourself: You need to start here. If your Bootloader is already on the device, then you can skip this step and continue here.

Please consider donation to Guido, PE1NNZ for all his work on the Software

First-time upload (burn bootloader) to the (tr)uSDX needs to be done via ISP programmer.

So if you don´t have a deticated programmer, the easiest way is, to use a cheap Arduino UNO Board (or compatible) and make it an ISP Programmer.

For this procedure, you need to download and install Arduino Studio Software,

Connect your Arduino UNO to you PC via USB, Start Arduino Studio Software, then Navigate to File -> Examples -> 11. ArduinoISP -> Arduino ISP:

A new Window will open, and after checking under Tools -> Board, that you´ve selected the right Board:

and have set the correct Port of your Arduino UNO (in my case COM5, in your case it might be a different one):

you can simply upload the sketch to your UNO:

If the Upload was successful, you should see the following message in the Bottom of your Window:

In case you didn´t enable all the debugging messages it also might look more like this:

Now the Arduino is ready to be used as Programmer for the (tr)uSDX and you can close Arduino Studio.

Download (tr)usdx Bootloader:

This is the Same File for everyone.

Then get the Software AVRDudess.

Connect the Pins of Arduino UNO in the following Pattern:

To the ISP Header of the (tr)uSDX:

and power-up the uSDX (with either 12V Power Supply or USB Power Supply (ant/mic/key disconnected),

It´s also possible to supply VCC Pin of (tr)uSDX ISP Header directly from 5V Pin of the Arduino UNO. In this case DO NOT CONNECT EXTERNAL POWER

Then start AVR Dudess, and make the following Settings

  • Programmer: Arduino
  • Port: YOUR USB COM port
  • MCU: ATMEGA328P or ATMEGA328PB (depending on the Chip on your Board)
  • Baudrate: 19200
  • Flash (Write): truSDX-initial_Bootloader.hex (The file you downloaded here)
  • Fuses settings (enable Set Fuses): L:FF, H:D6, E:FD (Changed !!!)
  • Erase Flash and EEPROM

Then Hit Program.

Now disconnect the programmer from the USB COM port, and power up your (tr)uSDX. You should see your Serial Number on the Display.

Write the Serial Number down for later use. In case the number starts with 7000.. then there might be an issue with the fuse settings or bootloader.

Next Step is to Upload the Firmware via USB