Hardware Resources for Engineers and Makers

ATxmega256A3U - Full Board


Based on the powerful Microchip 8/16-bit ATxmegaA256A3U microcontroller, this SiliconHacker full board boasts a number of features that make the engineer's and maker's task of developing xmega microcontroller hardware and software products very efficient.

A feature summary for the board is:

  • The ATxmegaA256A3U plugs directly into a standard protoboard. It receives power directly from the protoboard's power bus, as well as to provide a simple, direct interface with the SPI, I2C/TWI and JTAG buses. (Please see our power supply products—powering a protoboard has never been easier from any DC supply in the range of approximately 5.5VDC to 18VDC!)
  • A series diode in the supply bus to protect the board against reverse polarity.
  • A green power-available LED.
  • Generous MLCC 0.1μF, 1μF and  10μF bypass and filter caps.
  • A reset pushbutton.
  • A 2 x 20 character LCD display with backlight and contrast adjustment.
  • Four LED and push button I/O interface groups. Each LED and button is strappable for its active polarity (active-low or active-high). In combination with the LCD display, these are very effective tools when developing and testing new HW and code.
  • A microSD socket with memory present/absent detect. (A FAT32 driver, readonly in the current rev, is also available here.)

A feature summary for the microcontroller is:


  • A μB USB port.
  • A 32KHz crystal.
  • A socketed main crystal.
  • An Atmel JTAG programming port.
  • An Atmel PDI programming port (including a HW hack for the xmega programming issue).
  • Strappable selection to enable either the SPI-C or SPI-E bus on the card end pins. (The one NOT selected can still be accessed via the direct PORT socket headers.)
  • Strappable selection to enable either the TWI-C or TWI-E bus on the card end pins. (The one NOT selected can still be accessed via the direct PORT socket headers.)
  • Socket headers for the TWI pullup resistors.
  • Four ground pins for instrumentation such as oscilloscopes, logic analyzers, and DVMs.
  • PORTC, PORTD, and PORTE socket headers provide direct I/O access for whatever you may need.
  • All features clearly labeled.
  • FULL SOFTWARE SUPPORT. See here for the complete AS7 project and C++ drivers and test benches for all full board features! [Note: USB driver code not yet complete as of the release but will be coming soon.]


ATXmegaA256A3U Full Schematics - Full Board