New Dev Board

We are running out of space on our T20 FPGA. Let's build a dev board for a T120 to give us plenty of space for upgrading.

The board should still be an IO breakout board like the T20F256 giving us IO headers to connect to. This makes it easy to fix mistakes with the peripherals since they are on their own daughter boards.

We will use the T20F484, which also has 16/32x DDR interfaces, which we should investigate using. We can also include SDRAM in case DDR doesn't work.