Open Bouni opened 5 years ago
@Bouni the default serial_8250_omap does a bad job at real RS485, sadly you'll need to rebuild the kernel and switch to CONFIG_SERIAL_OMAP.
Disable:
CONFIG_SERIAL_8250_OMAP=y
CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP=y
Enable:
CONFIG_SERIAL_OMAP=y
Regards,
@RobertCNelson Thanks for the fast answer! Are there instructions somewhere on how to do that? Never built a kernel before. I assume that its smart to do it on a PC with more power an cross compile, right?
Hey,
I'm using the Debian 10 image with Kernel version 5.4.66-ti-r18.
Based on the UART4-RS485 overlay, I wrote an overlay for UART5 using P8.37
(Tx), P8.38
(Rx), P8.32
(de/re).
I have the problem that gpio0_11
doesn't go high when transmitting.
Is this still a problem of serial_8250_omap
in Kernel version 5.4?
Regards, Florian
I try to get RS485 with the Waveshare CAN/RS485 to work on the latest Debian Buster Image (Debian 10.0 2019-07-07 4GB SD IoT) but had no success so far.
Since 2016 I had this cape running with a 3.8.XX Kernel but thought its time to update. Unfortunately a lot changed since than, so my approach from back then does no longer work.
On 3.8 I just enabled UART4 using
cape_enable=capemgr.enable_partno=BB-UART4
in the uEnv.txt and then used this ioctl (python) to switch RX/TX:The Waveshare Cape uses Pin P9.42 (GPIO0_7) for switching RX/TX. For I don't know what reason, this no longer works.
I tried to use the BB-UART4-RS485-00A0.dts uBoot overlay without success, but that's no surprise because it specifies P9.27 to switch RX/TX.
So I made a copy of that file and changes all
P9_27
forP9_42
andgpio3_19
forgpio0_7
, compiled it successful, copied it to /lib/firmware and put it into uEnv.txt.Still no success :-(
By the way, receiving works but again, that's no surprise.
Any ideas what i do wrong?