Part 1b ECAD+Arch Labs - Trouble Shooting

This page will be added to by ECAD Lab demonstrators as issues are found with the new labs.

Before installing guest additions

Ubuntu needs you to run this

sudo apt-get install build-essential linux-headers-`uname -r` dkms

or you miss some essential part, and its "generic build" doesn't give you shared folders support.

Debugging the new labs

RISC-V tools not found

riscv32-unknown-elf-as -c -o main.o main.s
make: riscv32-unknown-elf-as: No such file or directory
make: *** [main.o] Error 1

means they failed to source the setup.bash script in their terminal as described in the instructions

Debouncer testbench error

There was an error in the debouncer testbench script ( that compiled


This should be:


This was only present for about 20 hours, but some people have downloaded in that time.

Pins file voltage clashes

The de1soc_pin_assignments.qsf file was missing some voltage settings, which caused builds to fail. This is now fixed - re-download the file.

VirtualBox graphics slow/corrupted

Corrupted graphics means 3D or 2D acceleration is enabled in VirtualBox. Turn it off, it doesn't work.

Unity can be slow without 3D acceleration on some machines - the solution is to disable Unity 3D features, eg:

Don't put your files in shared folders

Quartus will randomly hang if the project lives in a shared folder: VirtualBox probably gets filesystem locking wrong in some way causing concurrency fun. Don't do it.

Quartus doesn't detect DE1-SoC

In the shipped VM the 'Altera DE-SoC' USB map is too restrictive - it's keyed on serial number.

Go into the VM settings, Ports, USB. Select Altera DE-SoC [0134], click on USB plug with orange circle (right hand side). This is a filter to match USB devices. Clear all the boxes except Name, Vendor ID and Product ID. (clearing Product ID as well may work). OK.

No 'Devices' (or other) menu in VirtualBox

Lack of a VirtualBox 'Devices' menu on a VM prevents attaching guest additions, shared folders, USB, etc

Spotted on a Mavericks Mac on VBox 5.0.6: highlight VirtualBox control panel window, go to menu bar, VirtualBox -> Preferences, go to User Interface, ensure all tabs are shaded. Any unshaded tabs will be hidden.

General hints and tips

The internal signals of my modules don't show up in modelsim's wave viewer

Try disabling optimisations when compiling your design : go in Compile -> Compile Options ... and tick "Disable Optimisations by using -O0"

My Yarvi has don't cares (xxxxxxxx) in a register/memory

While Yarvi registers are preinitialised, in simulation memory is not. If you make an uninitialised memory location and read it, for instance:

int a;

the value will be 'xxxxxxxx', which will then propagate.

Quartus won't start

Help! My design doesn't work! What do I do now?

Argh! I'm never going to get this finished on time!

Synthesis/Compilation takes too long!

Quartus seems to have programmed my FPGA with an old version

CompArch/Teaching/ECADlabs (last edited 2015-11-10 17:26:26 by TheoMarkettos)