This page documents using the Xilinx impact tools for designing, testing and generating programmable logic for the Balloon.
The Balloon logic is written in VHDL. It is split into core parts needed for the functionning of the board and parts you might want to add for your own projects.
Xilinx provide cost-free tools for both Linux and Windows to process the VHDl to produce uploadable binaries. The Tools used to be called 'impact', but are currently called 'Xilinx ISE'.
Generating XSVF file
First download and install the stupendously huge dollop of software.
Run ISE. On Windows it should have added itself to your Start menu. On GNU/Linux run it from a prompt:
. xilinx91i/settings.sh xilinx91i/bin/lin/ise
Open the project file in balloon svn: trunk/vhdl/fpga/l3fpga.ise.
This may ask to convert itself from an older ise format. Let it.
Select 'Process'->'Implement top-level module' and let it churn through. This processes the design, but does not generate the bitstream to upload.
To generate the bitstream, select l3fpga - Behavioural (l3fpga.vhd) in the top-left 'sources' tab window. Then you can double-click on 'Generate programming file' in the 'Processes' window below on the left. This should produce an l3fpga.bin file in trunk/vhdl/fpga/, which you can upload.
Using iMPACT (obsolete?)
Run impact. On Windows it should have added itself to your Start menu. On GNU/Linux run it from a prompt:
. xilinx91i/settings.sh xilinx91i/bin/lin/impact
You can't do anything without creating a project so far as I can see. So File->New and give it a name.
Then you get a dialog called 'iMPACT - Welcome to iMPACT'. Select the option 'Prepare a Boundary-Scan file', and the output type XSVF. Then 'Finish'.
This produces a file dialog 'Create a New SVF File'. Choose a place and name to save the resulting file. OK on dialog saying that next you will add a device. Now load the relevant .jed file. (e.g. from svn/trunk/vhdl/cpld). The correct device (XCR3256) and JTAG chain should now be displayed. Right click on this and select 'Program' to generate the XSVF file. Select verify in the dialog and 'OK'. The XSVF file will be written.
You can either program the device directly from here, or quit iMPACT and use bbl (or playsxvf) for uploading.