OLED Controller MCU for 1 or 2 RF Step Attenuators SPI Modules

NEW: With Arduino Nano and 1.3" OLED

This small PCB (41 x 79 mm) incorporates an Arduino Nano, a rotary encoder, a 3.3V voltage regulator, a 1.3" OLED and 2 connectors for connecting 2 RF attenuator modules (see above).

The idea is to make an independent digital RF attenuator with it's own user interface. 

The controller supports 0-31 dB control range with one RF attenuator module, or 0-62 dB  control range with 2 RF attenuator modules. This is selectable with jumper J5. Upon power-on, it starts at the last attenuation value set. Then the rotary encoder controls the attenuation value, the MCU controls the PE4306 chip of the displayed value and then stops sending data in order to reduce any RFI to other circuits. 

J1 is for the 5V DC input.

J2 and J3 connect to one or two series connected RF step Attenuator Modules. They carry the SPI bus plus the 3V DC power for the RF Step Attenuator Modules.

The rotary encoder and the OLED are mounted on the bottom side of the PCB. 

The RF step Attenuator PCB Modules are sold seperately.