Terasic’s DE0 is a very beautifully engineered piece of hardware. It has everything necessary to run most PDP11 models, with enough room left in the FPGA for peripherals, though with the terminal included, an 11/45 becomes a tight fit, and 11/70 is out of the question. That is, unless you leave the floating point out, which is entirely possible if you want to run 2.11BSD on the board – just make sure to install the latest patches, and compile the kernel with the fpsim option enabled.

There is only one slight flaw in DE0 that I can think of – it does not have a DB9 connector for a serial link. The board does have the connections, and it would be easy enough to solder header pins on. But I decided that I did not want my substandard soldering to mess up this pretty board. Instead I came up with the idea to implement a simple terminal, and use the PS2 and VGA connectors as a console interface instead of the serial link. And, implementing a terminal proved to be easier than I expected – the only thing that took more time than I hoped was to get the VGA signal timing exactly right.

Anyway – the terminal is currently very simple. It only deals with carriage return and linefeed, and does not understand other control characters or escape sequences. Maybe sometime I will make it resemble a VT100, but don’t wait for it. Still, simple as it is, it works well enough to play with RT11 or Unix V7 – or any of the other systems, if you’re not hoping for correctly working terminal tricks. Just hook up an old LCD screen or CRT that can do 640*480 and a PS2 keyboard, put an SD card with a disk image in and watch the blinkenlights do their magic!

What’s nice about the embedded terminal is that there is no need for a PC at all – great for demonstrations.