Fomu on IceStudio Nightly¶
Fomu is currently not supported in the stable releases of IceStudio. Development or nightly releases need to be used.
“Hello world!” - Blink a LED¶
The canonical “Hello, world!” of hardware is to blink a LED. The
icestudio contains a Blinky example in ICE format.
Blinky_BoardTop.ice wraps Blinky, showcasing how
to use the Design Under Test (DUT) as a black box.
Blinky_BoardTop.ice from Icestudio
and use the buttons at the botton:
Check that the selected board is the Fomu.
Click on the button with a ‘microchip’ icon, and a modal window will open.
There, select the device (UP5K) in the first dropdown list and the board (Fomu) in the second list.
Click on the Verify button for checking the design.
Click on the Build button for having the design exported to Verilog, synthesised, placed, routed and, finally, the bitstream generated.
Click on the Upload for sending the bitstream to the board.
After each of the steps is executed, the corresponding log can be shown through button View command output.
You should see the rainbow pattern in the Fomu as soon as the Upload step is finished:
However, that’s just the beginning of the trip…
A feature in IceStudio Nightly named “board rules” allows predefining assignments for I/O pins. For instance, Fomu needs to disconnect its USB communication stack when writting raw HDL. Therefore, it is always necessary to define and set pins usb_dn, usb_dp and usb_dp_pu. Option board rules does so, allowing a cleaner graphical desing.
Blinky_BoardTop_rules.ice, which is the result of using this feature
in the Blinky example. As you see, USB pins need not to be defined explicitly:
Instead, ensure that option board rules is activate in the board properties:
As shown in the screencast, you can inpect the specific rules applied to each pin by using the “View board rules” button in the board properties window.
The same rules can be applied to modules lower in the hierarchy. For example, open
Blinky_rules.ice and compare with
Find more info about features of IceStudio (such as collections or plugins) in the documentation.