The DSLogic open source logic analyzer is on its second release (the plus version) and [OpenTechLab] has a comprehensive review of the new model, which, unlike the original model, includes a different method of connecting probes and provides a separate ground for each input pin.
The device is pretty simple inside with an FPGA, a RAM, and a USB microcontroller. There’s also a configuration EEPROM and a switching power supply. The device stores up to 256 megabits internally and can sample 400 million samples per second on 4 of its 16 channels. [OpenTechLab] even puts the board under a microscope and maps out the input circuit.
Unlike a lot of USB logic analyzers, the new arrangement of probes and dedicated ground allows the probes to use a very short flying lead that connects to a thin piece of coax. This improves the logic analyzer, but [OpenTechLab] notes that without termination resistors, the probes can modify the signal and he even shows a simulation of the effect along with an actual comparison of normal flying lead probes and the ones provided by the DSLogic.
[OpenTechLab] was an active contributor to Sigrok, and he discusses how the original DSLogic software was an unauthorized fork of Pulseview with all the Sigrok licensing and branding removed. Some of the video covers the controversial status of the DSView software which started life as PulseView.
We reviewed the original version back in 2015. Logic analyzers are simpler than used to be, both because you rarely have access to too many internal connections and the availability of cheap FPGA hardware.