Sea-Picro EXT is a ProMicro-shaped breakout board with RP2040. The Sea-Picro is designed by joshajohnson. The open source hardware project can be found at the GitHub repo https://github.com/joshajohnson/sea-picro.
Features
- No on-board LEDs
- The version in this shop does not come with the power LED. It has been removed intentionally.
- Non-castellated
- To keep this affordable, this is the 1.0-ext instead of 1.0-ext-castellated.
- 16MB (128Mb) Flash Memory (W25Q128JV)
- You can enable a lot of features and layers. Never worry about the firmware size limit.
- Comparing to the ATmega32U4-based boards that come with 32KB, there is 500x more memory.
- 16MB is the highest amount of memory supported by RP2040 via dedicated QSPI bus. Other RP2040-based boards might come with less flash memory, depending on the off-chip memory used.
- If you use CircuitPython, some flash memory will be used by CircuitPython.
- RP2040 MCU
- It’s a low-cost, easy-to-source, powerful microcontroller with dual Arm Cortex-M0+ @ 133MHz, 264kB on-chip SRAM
- It’s possible to use the QMK firmware, QMK-based tools (VIA, Vial, Remap), CircuitPython Python-based (KMK firmware), Ruby-based PRK firmware, and Rust-based firmware keyberon
- Built in VBUS sense circuit
- For split keyboards, you can disable the SPLIT_USB_DETECT to avoid problems including keyboard wakeup problems. The VBUS sense (VBUS_DETECT) circuit is connected at GP19. It’s recommended to use `#define USB_VBUS_PIN GP19`.
- A single button for reset/bootloader mode
- For other boards, it is challenging to use two buttons to enter the bootloader. With this circuit, resetting the board, or entering the bootloader mode becomes easier.
- To enter the bootloader mode, short the RST and GND pin for two seconds. There will be a mountable USB mass storage device for UF2 flashing. Instead of QMK Toolbox, you can copy and paste the uf2 firmware. For some Linux distros, root privileges or udev rule modifications might be required.
- Pin compatible with most pro micro boards
- Legacy boards that connect RAW and VCC pins are not compatible
- RGB LEDs (such as WS2812B-5050, SK6812mini-e) usually require a power supply voltage above 3.5V or 3.7V. Although some people power RGB LEDs at 3.3V, this is out-of-specification.
- Mid-mount USB Type-C
- It is stronger than the fragile USB Micro B connectors, commonly found in Pro Micro clones.
- It allows lower profile keyboard builds.
- Both A-to-C, and C-to-C data cables are supported.
- You can plug in the USB Type-C cable either way with the flippable connectors.
- IO pinout compatible
- It’s IO pin compatible with some of the RP2040 breakout boards including Sparkfun RP2040 Pro Micro, and Adafruit KB2040 – RP2040 Kee Boar Driver
- 5V logic level shifter/converter
- There is an extra pin to provide data signal with a proper voltage level for communicating with RGB LEDs with built-in ICs.
- More pins
- Additional D+ and D- pins at the top
- Additional 5 GPIOs at the bottom
Important Notes
- You should flash a firmware before soldering. Improper soldering can make this board non-functional.
- Pin headers are sold separately.
- This is a hardware product for hobbyists. For advanced features or firmware-related questions, please visit other community sites or Discord channels.
- Charging-only USB cables do not provide data communications. You should use A-to-C, or C-to-C USB data cables.
Hunter Wei –
I would like to install circuitpython into this board, which .uf2 file should be used?