The Flashless Pico (UART) is an RP2350 powered board (as used on the Raspberry Pi Pico 2) with NO FLASH onboard. Firmware can be uploaded using either the RP2350s built in USB UF2 or UART bootloaders, it was created to enable quick and easy prototyping of RP2350 designs utilising UART boot.

On the opposite edge to the Micro USB connector there are two connectors used to control the board.

The 4-pin JST SH compatible connector (3v3 STEMMA QT/qwiic) is connected to a TCA9535 16-bit I2C I/O expander which is used to configure UART/USB boot mode (RP2350 SD1/BOOTSEL pins), reset the RP2350 (RP2350 RUN pin), and additionally interfaces with 13 pins of the RP2350 GPIO pins (GP8 to GP19 and GP23). Access to the I2C expanders address select lines (A0/A1/A2) is provided on the underside allowing up to 8 Flashless Pico to share the same I2C bus.

The 3-pin JST SH connector is the UART (RP2350 SD2/SD3) used to upload firmware and communicate after booting (Raspberry Pi 3-pin UART debug compatible).

To upload firmware over UART (or USB) the RUN/BOOTSEL/SD1 pins are configured using the I2C I/O Expander (see the UART Boot section of the RP2350 datasheet for the levels) and then the binary file is uploaded using 1M BAUD UART.

Care must be taken to ensure both RP2350 and I/O Expander do not drive GPIO pins at the same time.

Please ensure your address is full and correct before placing an order and be aware I'm unable to use some shipping methods to PO boxes.

Deliveries to the USA are sent using RoyalMail PDDP (Postal Delivery Duties Paid).