From time to time I need digital test signals on more than the two channels which my function generator provides. Say to test an SPI slave device I am developing and which needs clock, data and a select line.
I have cobbled ad-hoc test signals together by programming a microcontroller or a GAL in such situations, but was wondering whether there is some cheap-and-cheerful solution available off the shelf which would make this a bit quicker. Rough idea of the functionality:
- 8 output channels
- Support at least 5V, 3.3V, 1.8V output levels. Probably best to have drivers which take their output voltage from the target.
- No hard-and-fast target for the max. clock rate. 100 MHz?
- USB input to configure from PC. The whole thing could be just a little USB dongle, like the mini logic analyzers?
- Programmable by uploading a CSV data table or such, and/or by a graphical UI on the PC.
Does such a gadget exist? I'd buy a cheap one right away, or make one if open-source designs are around. If nothing is available, this might be a nice little project at some future time...