EncoderCAT - rotary encoder control by CAT interface

EncoderCAT provides CAT control by rotary encoders

Most modern amateur radio transceivers have a CAT interface for external control by PC based software.

The user manuals give details of the control code sequences for a wide range of controllable settings.
I shall refer to these setting as rig parameters.

There exists a small number of PC based CAT control applications, some of which offer comprehensive

control for a range of different radios.  Some are free. Some cost money.

Rig control parameters such as RF power, noise reduction level, vox gain, audio gain etc are typically

managed on a PC screen by slider controls.

EncoderCAT provides control for such parameters using low cost electro-mechanical rotary encoders.

These are devices which are typically used as volume controls in car radios.
They have remained available for purchase on eBay for the past 15 years or longer.
The price can be as low as £20 for ten encoders.

EncoderCAT was initially developed using a Yaesu FTdx101D and then extended for Icom radios.


The FTdx101D has dedicated rotary controls for the most commonly used functions.

In addition, a single 'Multifunction' control  can be assigned to one of a range of other rig parameters.

These parameters include DNR level and RF Power for which separate controls are desirable.
EncoderCAT provides such separate controls.


EncoderCAT is configured for a particular radio using the PC-based xCAT application.

Note that there is lot more configuration information in this document for Icom CI-V configuration
- because it is more complex than Yaesu. Kenwood, Elekraft.


When an encoder is rotated by one notch:

At 38400 baud, this all happens in 5ms, well before the next encoder notch movement occurs

OLED display panel

EncoderCAT has an optional small OLED display.
The firmware is designed to drive an I2C connected display which conforms to SSD1306 driver specification.

The display identifies the operated encoder and stays with that encoder until another is operated.
For each encoder, the user can configure for the OLED display  (with xCAT) :

My prototype uses a small 128 x 32 pixel monochrome display.
These are available from a number of eBay suppliers and cost approximately £4.00.

The display unit does not contain font data.
I have two proportional font character sets in the firmware:

 - one 16 bits high for the data and one 8 bits high for the description.

EncoderCAT cost

EncoderCAT components cost about £30 from Farnell electronics
(The cost may be more than this due to some minimum quantity constraints and post and packing)

G3VPX can supply the PCB for £4.

The main cost is a JTAG programmer.

The cheapest Atmel JTAG programmer is the Atmel-ICE supplied as PCB-only for £41 + VAT,

This is a fast programmer with built in debugging capability to work with Atmel's (free) Studio 7 system.

You need to make up a cable to use this device.  The connectors are in the EncoderCAT bill of materials.

G3VPX can supply preprogrammed Atxmega192A3 processor.
However, this project is likely to evolve / improve with feedback from users
  - you would then need a programmer to install the program updates.

See:  JTAG programmer