Wednesday, January 12, 2011

Atlys and HDMI on Linux

Xilinx App Note 495 describes sample implementations of DVI/HDMI receiver and transmitter on the Digilent Atlys board. I built the code using WebPACK 12.4, and it works as advertised: The colorbar test pattern displays nicely on my HDMI monitor.

Also installed Digilent's Linux version of their Adept tools for FPGA programming. They don't seem to have the full GUI version available, but the command-line tool was able to load my test code (as a WebPACK-generated .bit file) into the Atlys FPGA with no problem. Don't see any way to load code into the SPI flash: it appears that Windows-based tools are still needed for that.

Only one minor glitch: I use Debian, which isn't one of Digilent's supported distributions. In recent versions of Debian, the udev package doesn't allow plugin devices to have protection mode 0666, which means that the Digilent tools will only work if run as root.
The fix is to edit "/etc/udev/rules.d/52-digilent-usb.rules" and add a group:
SYSFS{idVendor}=="1443", MODE="666" GROUP="plugdev"
then any user in the "plugdev" group can run the Digilent tools. The /etc/group file should have a line like
where "jr" is my username.