Antenna tuner - ATU-100 EXT - Yet Another Firmware

Motivation

After I have bought a Chinese clone of N7DDC Antenna tune ATU-100 EXT I wasn’t really satisfied. The tuner was not able to work with my QRP transmitter. Also the shown power was very inaccurate. I have seen some room for improvement in the firmware. Unfortunately the original firmware of N7DDC was written under the mikroC IDE that is not available for free. So I decided to start the project from scratch with the Microchip MPLAB X IDE.

The original project by N7DDC

https://github.com/Dfinitski/N7DDC-ATU-100-mini-and-extended-boards

Imported Notes

This firmware only works with the ATU-100_EXT (7x7) hardware, the PIC16F1938 MCU and the OLED Display 128x64px. Before you start please make a backup of the original firmware and be sure that you can restore it.

- You act at your own risk!

Features

• Function menu on display – one button operation
• 10 memory slots for tune-settings one of them as a startup setting
• Calibration function for the integrated power meter
• Configurable Auto-Tune function
• Sleep function for battery saving
• Temporary Bypass function

Button functions

Button short pressed: _____ Start Tuning or select next item

Button long pressed: ______ Enter Menu or change value

Menu-tree

• Bypass ______Temporary bypass the current tune settings
• Load Tune __ Load tune setting from memory slots
• Save Tune __ Save the current tune settings in 10 memory slots
• Reset ______ Reset the current tune settings
• Setup
  • Tuning _____ Set tune parameters (Auto tune on/off)
  • Sleep ______ Set sleep mode and time
  • Calibrate __ Calibrate the power measurement at two points
  • Test _______ Test function for each relay
• About ______ Who did it

Calibration

The firmware includes a two point calibration function for the integrated power meter. It is recommend to calibrate on the lowest (max 10W) and highest (max 100W) used power level. For calibration you need a transmitter with adjustable TX power and a dummy load.

Programmer

For programming a PICkit3 programmer is used. When the ATU-100 is switched off, connect it in the shown way. After that switch on the ATU-100.

Programming Tool

If you only like to flash the firmware you can use the Microchip Integrated Programming Environment MPLAB X IPE. The needed hex-file you find in the dist folder.

Development IDE

For development the Microchip MPLAB X IDE v6.00 was used. The IDE is available for free on the Microchip web side.