Fun with NIOS II.

[Michael Field]

After hitting the PDFs, a few false starts and a bit of luck I've
managed to

- Use the DE0-nano System Builder to start a project, just the clock,
LEDs and buttons.
- Use QSYS (new in v11?) Build a system consisting of a JTAG UART, a
NIOS II CPU, 32KB of on-chip memory and an 8 bit output port, and wire
it all together
- Figured out how to add it into the Quartus project, and then figured
out enough Verilog to wire the NIOS II to the clock, buttons and LEDs.
- Work out how to build a "BSP" HAL - basically a custom software
run-time needed to initialise the hardware and bootstrap the C runtime.
- Wrote a little "hello world" in C, and worked out how flick the LEDs
using memory mapped I/O
- Downloaded it all to the DW0-nano

And it lives!