The Interfacer is a small low cost USB to UART and I2C Adapter (both 3.3V) powered by an RP2040 that plugs straight into a USB Type-A socket. Being powered by the RP2040 with 2MB FLASH it can be used with CircuitPython or Pico C SDK based firmware.

The serial UART connector is 3-pin JST SH compatible socket as used on the Raspberry Pi 5 UART.

The I2C ST/Qw connector is a 4-pin JST SH compatible with (3.3V) STEMMA QT. The SCL/SDA lines also have 1K resistors connected to additional GPIO lines allowing each one to have either pull up/down resistor enabled in software. The ST/Qw GPIO pins used are also capable of analogue input allowing them to be used for non I2C uses and when combined with the 1K pull resistors can be used to measure and detect external pull up/down resistors.

On the reverse side to the connectors there are three LEDs. In the middle is a red LED and over both UART and ST/Qw connectors are orange LEDs.

The RP2040 BOOTSEL button is dual purpose, once the RP2040 has started up it can be used for user input.

The GPIO pin numbers for the connectors, LED, button as listed below are also labelled on the PCB itself for quick reference.

Optional extras

You can also add an optional USB-C to Type-A adapter to your order which allows the Interfacer to connect to many mobile phones for USB CDC Serial UART access (where supported).