Hello everyone, We have installed a Controllino on our fruit press to do pressure logging and automation. For the pressure logging we use an SD card module connected to a TFT screen: https://www.adafruit.com/product/2050
Currently we run into the problem that the SD-card can not be found. It used to work previously, but for some reason it doesn’t any more.
This was only part of the solution. When I connected the Logic analyser, it worked. When I disconnected, it stopped working. The logic analyser input has a 100kOhm pull down resistor. I also had to add a small (27pF) capacitor in parallel with the resistor. This is on the clock line and seems to filter enough for proper operations.
We use a flatcable from the Controllino to the screen/SD card. SPI is not really made for over wire transmission and glitches can occur. There is 400V running next to the controllino/screen and even this filtering is not enough. We will move to a shielded cable as well for improved performance. Cable length is about 350mm.
Since the connectors on the Controllino are not pin compatible to Arduino, it would have been good if they were DB25 connectors or something similar. Those are easier and better to connect to and also more robust compared to flatcables. For prototyping, other equipment can be used.