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Mikoto

Specifications​

  • Pro-micro footprint
  • nRF52840 MCU
  • UF2 storage firmware
  • ZMK Firmware is highly recommended for wireless builds

Frequently Asked Questions (FAQ)​

This page addresses frequently asked questions regarding the Mikoto Keyboard Controller.

General Questions​

  • What is the Mikoto Controller?

    The Mikoto is a wireless-first keyboard controller based on the nRF52840 microcontroller. It features a Pro Micro footprint, making it suitable for custom mechanical keyboards, especially those designed for wireless (Bluetooth Low Energy - BLE) operation.

  • What firmware is compatible with the Mikoto Controller?

    The Mikoto is primarily designed for and best supported by ZMK Firmware. ZMK offers robust wireless features and power management ideal for nRF52840-based controllers like the Mikoto.

Firmware and Flashing (ZMK)​

  • How do I flash ZMK firmware onto my Mikoto Controller?

    Follow these general steps (always refer to the official ZMK documentation for the most comprehensive instructions):

    1. Obtain your .uf2 firmware file: This is typically built using ZMK's build system (e.g., GitHub Actions) specific to your keyboard shield and keymap.
    2. Unplug the Mikoto from your computer. If a battery is connected, it's good practice to disconnect it, especially for initial flashing or if issues arise.
    3. Plug the Mikoto into your computer using a USB-C data cable.
    4. Locate the RESET button on the Mikoto. It's a small physical button.
    5. Quickly double-press the RESET button.
    6. A new drive, typically named "MIKOTOBOOT" or "FTHR840BOOT" (or similar, depending on the bootloader version), should appear on your computer.
    7. Copy your .uf2 firmware file to this drive.
    8. The Mikoto will automatically eject the drive and reboot with the new firmware.
    9. After flashing, you can reconnect the battery if you disconnected it.

    If you're having trouble entering the bootloader, you can also check our general Entering the Bootloader troubleshooting page, keeping in mind the double-reset method for the Mikoto.

  • The "MIKOTOBOOT" (or similar) drive doesn't appear when I try to flash.

    • Ensure you are double-pressing the RESET button quickly and firmly.
    • Try a different USB-C data cable (ensure it's not a power-only cable).
    • Try a different USB port on your computer.
    • If a battery is connected, try disconnecting it and flashing with USB power only.
    • If the Mikoto is socketed, ensure it's properly seated.

  • My keyboard doesn't work after flashing ZMK firmware.

    • Verify you're using the correct .uf2 file built for your specific keyboard shield (e.g., yourshield_left.uf2, yourshield_right.uf2 for splits).
    • Double-check your ZMK configuration files (e.g., <shield_name>.keymap, <shield_name>.conf, <shield_name>.overlay).
    • Attempt to re-flash the firmware.
    • The firmware file might be corrupt. Try rebuilding it.
    • Consult the ZMK documentation and community for ZMK-specific troubleshooting.

Hardware & Wireless Issues​

  • My Mikoto isn't being recognized by my computer (not even for flashing).

    • Follow the troubleshooting steps for the bootloader drive not appearing (see above).
    • Inspect the USB-C port and the controller for any physical damage.
    • If socketed, confirm all pins are making good contact.

  • One or more keys on my keyboard aren't working.

    • This is often a hardware issue with the keyboard PCB, switch soldering, or the switch itself, rather than the Mikoto.
    • Check solder joints for the switches.
    • Ensure switches are correctly inserted into hot-swap sockets (if applicable).
    • The switch might be faulty; try replacing it.
    • Verify your ZMK keymap correctly defines the non-working keys.

  • My wireless keyboard (or one half of a split) isn't pairing or connecting.

    • Ensure the battery is charged and connected with the correct polarity.
    • Follow ZMK's Bluetooth pairing and bonding reset procedures.
    • Check for potential interference from other wireless devices or large metal objects.
    • For split keyboards, ensure both halves are flashed with their respective _left and _right firmware and are attempting to pair with each other as per ZMK documentation.

  • My battery drains very quickly.

    • Use a LiPo battery with the correct voltage (typically 3.7V).
    • Check for any shorts on the PCB or controller.
    • Ensure your ZMK configuration has appropriate power-saving features enabled.
    • The battery itself could be old or faulty.

Layout and Configuration (ZMK)​

  • How do I configure my keyboard layout with ZMK?

    Keyboard layouts in ZMK are defined via a keymap file (e.g., your_keyboard.keymap) in your ZMK user configuration repository. Refer to the ZMK Keymap documentation.

  • Where can I find pre-made ZMK configurations or keymaps?

    Many keyboard designers and communities share ZMK configurations on GitHub. Search for your specific keyboard PCB or shield name along with "ZMK config."

Community and Support​

  • Where can I get more help with my Mikoto Controller and ZMK?

    • The official ZMK Discord server is an excellent resource for ZMK-specific questions.
    • Consult the documentation for your specific keyboard PCB or kit.
    • Explore online keyboard communities like Reddit (e.g., r/olkb, r/ergomechkeyboards) or relevant forums.

This FAQ is a starting point. Always refer to the official ZMK documentation and your keyboard's specific documentation for the most accurate and up-to-date information.