Having good test equipment is essential to hardware hacking when you want to see what is going on ‘inside’ the devices you are hacking. A signal analyser is a great tool for digital work, but can be a bit pricey for the amateur.
Luckily the Chinese company LCSoft sells a development board based on the CY7C68013A chip that acts as a USB logic analyser (approx $AU10 on Ebay). This article explores initial steps in getting such a board working under Ubuntu 12.04 using the latest Sigrok and PulseView software.
The LCSoft board attempts to emulate more expensive USBee and Salae Logic devices. The corresponding software to these does not appear to work well with these boards under Ubuntu. Until very recently Sigrok appeared to be a poor second choice – while it captures the data, it is a command line tool so the data needs to be loaded through a separate software to be viewed. However, now PulseView is in its initial release and looks quite nice.
To install Sigrok and PulseView on Ubuntu follow the instructions provided in the wiki. The instructions work very well if they are followed directly and all dependencies are met and are easier than the README and INSTALL instructions packaged with the tarballs. Once libsigrok, libsigrokdecode, sigrok-cli and pulseview packages are installed on Ubuntu, it is important to include the fx2lafw driver. Instructions for downloading and installing this driver are found in its wiki page. Note that the downloads have moved to a different page.
At this stage you should be able to plug in your board and switch it on. Once the board is on, run PulseView. You should see a Salae Logic device listed if you have the bridge fitted to the eeprom on board the analyser. If not, you may get an error accessing the analyser. There are instructions for removing this error. After this PulseView should report the device as Cypress FX2.
The sigrok blog also has a page dedicated to the LCSoft board, which contains further information and troubleshooting. This highlighted the fact that it isn’t a good idea to wire the analyser directly into logic circuits. The next step will be to build a suitable clamping circuit.