x0xlarge CPU

x0xlarge 2020 with box and installation booklet
42,00 €
42 is the answer to life, the universe, and the price of the x0xlarge 2020 edition


The x0xlarge 2020 is the new version of the x0xlarge, refreshed by Anton Savov. The x0xlarge is a CPU expansion board for the Adafruit x0xb0x, offering 16 times more flash storage, 8 times more ram, 8 times bigger EEPROM, PWM, 8 channel 10 bit A/D converter, ISP connector, Midi SysEx firmware upgrades and loads of spare pins.

Unlike the previous versions (made by xlarge/yhype), the x0xlarge 2020 also comes with an on-board FRAM memory chip, which has a much higher lifetime than the EEPROM in the x0xb0x. It comes preloaded with banks full of famous and less-famous TB-303 patterns to inspire.

Compared to the original CPU you get:

  • much more stable bootloader with advanced features
  • easy upgrading via midi
  • great potentional for DIY firmware due to huge storage space
  • more accurate clock
  • hardware debugging (in combination with c0nb0x)

All x0xlarge come preinstalled with n0nx0x2, which is an attempt to copy but also improve the concept of the original TB-303. Keep in mind you need a new front panel to enjoy this firmware. In case it's not your cup of tea, you can also install the Adafruit firmware, SokkOS, MarOS or develop your own firmware.

NOTE: Installation requires removing the original Atmega MCU and EEPROM from the x0xb0x. This is fairly simple as both are usually in a socket. If unsure, please check before ordering, or send a picture of the internals.

Every x0xlarge 2020 comes with a short instruction manual to help with installation. Download here: x0xlarge 2020 Version Manual_Single_Page.pdf


  • contains atmega 2561 cpu with:
  • 256k flash (16k on the original cpu)
  • 8k SRAM (1k) 
  • 4k EEPROM (512b)
  • PWM 
  • 8 channel A/D
  • 16Mhz
  • 4Kb FRAM memory
  • ISP connector
  • lots of spare pins
  • open source design: schematic (= original x0xlarge schematic, update schematic and KiCAD source files will be posted soon)