Topic: iCE40 FPGA add-on
To let people use Clifford Wolf's IceStorm package to develop FPGA projects directly on the Novena, I've build a little mezzanine board that fits between the FPGA socket on the Novena and the GPBB (or other similar boards) and provides a Lattice iCE40HX4K FPGA.
The first version of the board worked well with a single wire bridge hack and a little tricky soldering, and I've drawn up a second bug-fixed version. My first batch of these revision 2 boards is being manufactured at DirtyPCBs just now; I'll post again if there are any problems, but I expect this to work as it's just a minor improvement on the previous model.
My current plan is to write a simple bus-bridge and memory controller for the Xilinx that can be shared by any iCE40 projects, so that people can do all their FPGA development work using only the iCE40 on the Novena itself, and essentially ignoring the Xilinx part. So far I've only written enough to let us push the bitstream into the iCE40 from the Xilinx, but that's working well, and the board is perfectly capable of running a blinkenlights bistream driving the GPBB's LEDs.
If anyone's interested in this project, my latest post describing it is here:
and the previous posts at the same site.
The board design is open source (under the same Apache license as Novena) and available here: https://www.jamiecraig.com/novena/Revision%202/
with the software for programming it and the Xilinx bitstream for a basic loader here:
I won't be selling any of these (no time for production myself) but I'm more than happy for anyone who wants to build and sell them to do so. If anyone else builds one, let me know - any feedback's always appreciated.