C1 - Non-Isolated Controller


The C1 module is a non-isolated controller: this means that the signals, power and grounding from the PC are directly connected to the SPI Rack. For RF applications this is typically not a problem, but it might create unwanted ground connections/loops for sensitive DC setups. For DC measurements, use the galvanically isolated C1b/C2 combination.

Below is a block diagram of the module. Inside is an ARM microcontroller which facilitates the communication between the backplane/modules and the PC. The microcontroller only acts as a go-between: at the moment of writing it contains no routines to control the modules by itself. All the data to the individual chips in the modules comes from the PC code. This allows for easy and fast development, at the expense of exact timing. If necessary, control routines could be added.

S5i block diagram

The module connects to the PC via a virtual serial/COM port over USB. This provides easy interfacing from almost any programming language/development environment. If you’re running MacOS, Linux or Windows 10, there is no need to install drivers as the OS has them build in. For earlier versions of Windows, the drivers can be found in the GitHub repository here: https://github.com/mtiggelman/SPI-rack/raw/master/drivers.zip For more information on the software, see the software pages.

Firmware Version

The table below shows the firmware versions for the microcontroller in the C1 and the changes with each version.

Version Number Changes
v1.3 Add firmware version readout over USB
v1.2 Added SPI write lock on Supply Monitor interrupt
v1.1 Added SPI write lock at Power On Reset
v1.0 Initial version, for prototype C1 & C2