linda Posted July 7, 2017 Share Posted July 7, 2017 Hi, I've tried to change the default console from ttyS0 to ttyS3, using the mainline kernel but I don't get it to work. Modifying boot.cmd I managed to change the tty's baudrate like this: "if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "${consoleargs} console=ttyS0,38400"; fi" after recompiling with "mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr" it gave me an 38400-baud-output begining with line "Loading, please wait...starting version 229" But changing the settings to use ttyS3 does not work at all: "if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "${consoleargs} console=ttyS3,38400"; fi" after recomililation ttyS3.is simply dead. Using the following string works like a charm with the legacy kernel! "if test "${console}" = "serial" || test "${console}" = "both"; then setenv consoleargs "${consoleargs} console=ttyS3,38400n8"; fi" (The "n8" suffix after the baudrate does not seem to matter at this point.) I tested the following armbian versions with the same result. 5.27.170614 nightly Ubuntu 16.04.2 LTS 4.11.1-sun50iw1 and 5.31.170619 nightly Ubuntu 16.04.2 LTS 4.11.1-sun50iw1 Link to comment Share on other sites More sharing options...
martinayotte Posted July 7, 2017 Share Posted July 7, 2017 You will need to tweak the Main DT to enable the uart3... Link to comment Share on other sites More sharing options...
linda Posted July 8, 2017 Author Share Posted July 8, 2017 Is the problem resolved in the following updates? The modification of the serial console to ttyS3 is absolutly essential for me. With the legacy kernel it worked without any problems.. Link to comment Share on other sites More sharing options...
zador.blood.stained Posted July 8, 2017 Share Posted July 8, 2017 6 minutes ago, linda said: Is the problem resolved in the following updates? No, because it's not a problem. Peripherials like UART, I2C, SPI are disabled by default and pins are configured as plain GPIO, and DT overlays can be used to change this. Link to comment Share on other sites More sharing options...
linda Posted July 9, 2017 Author Share Posted July 9, 2017 Thank you very much for pointing me in the right direction. I wasn't aware of the possibility to apply overlays to the device tree. And I didn't want to change the master DT because of loosing my changes in case of updates coming from armbian. Consulting the armbian documentation https://docs.armbian.com/User-Guide_Allwinner_overlays/ I found out there are already overlays supplied for various purposes and I just used: "/boot/dtb/allwinner/overlay/sun50i-a64-uart3.dtbo". After activating the overlay in "ArmbianEnv.txt" I was done. Great! 1 Link to comment Share on other sites More sharing options...
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