Enabling UART device tree overlay

dealerpriest

Hello!

I'm trying to follow the instructions in the wiki on how to enable a device tree overlay.
The instructions are here: https://github.com/BelaPlatform/Bela/wiki/Load-a-device-tree-overlay
I have the latest Bela image running, so I've followed the instructions where I should add a row to uEnv.txt
I've added the following row:
uboot_overlay_addr3=/lib/firmware/BB-UART4-00A0.dtbo

My understanding is that this should enable UART 4 on the BBB on startup. Hence I thought that I should be able to find the UART as ttyO4?
But when I run ls -l /dev/ttyO* I get nothing. Any advice on what I'm doing wrong? Are the hardware serial ports not labelled this way (ttyOx)?
Side question. What does 00A0 stand for in BB-UART4-00A0.dtbo?

LiamDonovan

Hi dealerpriest

You can only use uboot overlays if you have a v0.3.4 or above image on the emmc. If you have booted from an SD card with a recent image but have an old Bela image or a bb.org image on the emmc, you need to copy the newer boot loaders to the emmc with the script at /opt/Bela/bela_bootloader.sh

dealerpriest

Hehe. Found out myself that the hardware serial ports are actually labeled ttyS* and not ttyO*. I don't know why that is, as I haven't anywhere read of that being the case. Only read that it should be ttyO* on several places throughout the webz. Anyways. Have it working fine now. If anybody needs help getting hardware serial up and running on the Bela, give me a shout :thumbup:

giuliomoro

And to make things more complicated, on Debian Wheezy (e.g.: Bela images before v0.3) it was /dev/ttyG4. Go figure!