OLED Controller MCU for 1 or 2 RF Step Attenuators

This compact PCB assembly (41 × 79 mm) integrates an Arduino Nano, a rotary encoder, a 3.3 V voltage regulator, a 1.3-inch OLED display, and two board-to-board connectors for interfacing with up to two external RF step attenuator modules.

The purpose of this design is to provide a standalone digital RF attenuator controller with its own local user interface. The controller supports a 0–31 dB attenuation range when used with a single RF attenuator module, or a 0–62 dB attenuation range when two attenuator modules are connected in series. The operating range is selected via jumper J5.

Upon power-up, the controller automatically restores the last programmed attenuation value from non-volatile memory. Attenuation is adjusted using the rotary encoder, with the selected value displayed on the OLED. The microcontroller programs the PE4306 RF attenuator IC accordingly and then suspends SPI communication, minimizing digital activity and reducing the potential for RF interference (RFI) with surrounding circuitry.

Power and Connectivity

J1: 5 V DC power input

J2 / J3: Interfaces for one or two series-connected RF step attenuator modules
These connectors carry the SPI control bus as well as 3.3 V DC power for the RF attenuator modules.

The rotary encoder and OLED display are mounted on the bottom side of the PCB, allowing flexible mechanical integration and front-panel mounting options.

Please note that the RF step attenuator PCB modules are sold separately and are not included with this controller board.