I've made a 2 letter 7 segment display using this LED driver
when I connect it with a 10-20 cm cable to my MCU board it all works OK, but fails when on about 2 m. also I have 3 other mosfet outputs going through the same cable, the cable is YSLCY 10 x 0.5 so there's 10 wires:
- MOS1 GND
- MOS2 GND
- MOS3 GND
- MOS and 7SEG shared +12V
the cable is shielded, so it should be good from outside EMI, but fails miserably as I recently found out, especially when I also switch ON any of the PWM MOSFET outputs.
Later on I tried to separate the mosfet outputs from the signal part, and it was a bit better, but still not acceptable. I've read about using twisted pair cables, termination resistors, ribbon cables, not exactly sure if that would work.
Also application note here https://www.st.com/resource/en/application_note/dm00038253-led-array-drivers--stmicroelectronics.pdf on page 52, mentions filtering, also not sure what to do.
So looking for help or a guideline on what to do??
If I cannot fix the SPI noise, I was thinking of putting LED driver to my MCU board and connect the 16 LED outputs with cable to my LED series (hoping that would not have interference as well), or just use something else other then SPI