Summary

The Butterfly Light is comprised of the USB Cocoon and the Spartan 3E Cocoon which paired together create an FPGA development board. The Butterfly Light is best suited for developers who prefer to create their own daughter boards instead of utilizing the "Wing" peripheral system. The Butterfly Light exposes the maximum amount of I/O of all available Butterflies. It is also well suited for use with the Logic Analyzer software which implements a 100Mhz, 32 channel Logic Analyzer.

Upgrade Path

The Butterfly Light can be upgraded to the Butterfly Flight with the addition of the Spartan 3E Wing Adapter. The Spartan 3E Wing Adapter opens up access to the library of Wing peripherals.

Included Modules

• USB Cocoon
• Spartan 3E Cocoon

Specifications

• USB Cocoon
  • Three independent power rails at 3.3V, 2.5V, and 1.2V.
  • Power supplied by a power connector or USB.
  • High speed two channel USB connection for JTAG and serial communications implemented with FT2232.
  • JTAG and USB connections are protected by high speed buffers.
  • EEPROM memory to store configuration settings for FT2232 USB chip.
  • Open Source design that includes Schematic and Board layouts in Eagle format.
• Spartan 3E Cocoon
  
  • 8MHz oscillator that can be used by Xilinx's DCM to generate any required clock speed.
  • VTQFP-100 footprint that supports Xilinx XC3S250E and XC3S500E parts.
  • Bank 0/1 and 2/3 can be jumpered to support 1.2V, 2.5V, or 3.3V.
  • JTAG, Serial, and power connections are routed to the the top header.
  • Power and GPIO are routed to the side headers.
  • Board can be used with Bread Boards if only the outside row of the side headers is populated.
  • Open Source design that includes Schematic and Board layouts in Eagle format.

Limitations

• The Butterfly Light does not have any ability to retain its application when it is removed from power. Every time the hardware is plugged into the USB port the application needs to be loaded to the hardware. For prototyping or tethered applications this is desirable behavior, for stand alone applications there are  projects in development to address this limitation.

Resources

• Butterfly Loader - A software project to load FPGA bitstreams to the Butterfly Light.
• All resources for FPGA Developers.
• Purchase the Butterfly Light.

Pictures