How to reverse engineer an unknown LED display PCB (Data Display DL110)
Aimed at beginners and intermediate electronics hobbyists this is a short video describing how to reverse engineer an unknown LED matrix board which came with all driver chips and buffer circuitry. This was salvaged from an old cinema lobby display board but the original control logic was missing. I show you how to do basic reverse engineering tracing back the data, clock and row scan signals to the input connector to determine it's pinout.
Almost all dot matrix displays will use multiplexing and will scan the rows sequentially whilst data for that row is 'shifted in' via shift registers for that row. Once data has been sent, the output is latched and then it moves onto the next line and so on. The previous line is then disabled so that only one row of LED's are lit at once. This is done so fast the human eye sees all lines lit at once through persistence of vision.
This method can be used for any unknown circuit really. All you need is to find the datasheets for the onboard chips and start tracing where the signals go.
Link for C++ source code (Arduino) to get the display as shown in the video
https://www.adrian-smith31.co.uk/blog...
Data Display DL110