OpenMarine

This HAT is sold by Waveshare: https://www.waveshare.com/2-ch-rs485-hat.htm

After an update a couple of months ago you will get a warning using:


that the overlay has been renamed. The above is still the instruction in the Waveshare WIKI for your config.txt.

Previously, the above line did work. Kind/of.
And also note that enabling or disabling SPI in the "Raspberry Pi Configuration" before the update did not do any difference (!).

After some kernel updates; in order to have this HAT work try:


And make sure SPI is enabled in the "Raspberry Pi Configuration" application.
You may find only the second dtoverlay line when googling.
At least here, both lines and enabling SPI is required.

Now i get the RS485 NMEA0183 data from the sensor stably and reliably on /dev/ttySC0.

There are differences between using the HAT with RPi4 and RPi5. I use a 5.
Some kernel-dude indicated that it might look as it's working on the Rpi4.

I'm posting this because the Waveshare WIKI is *NOT* updated.

HTH

/Dany

There are even more HATs affected. For example, Waveshare RS485 CAN HAT (B).
More about this issue on GitHub
https://github.com/raspberrypi/linux/issues/6962

I have this board working on two different installs on R-Pi 5's. One is on OpenPlotter 4 and the other on a bare install of Trixie. Both work really well. I am also using an m.2 as storage. The wiki does seem to work. Guess they updated it?