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On 6/17/22 20:44, Lennart Sorensen
wrote:
On Fri, Jun 17, 2022 at 06:45:02PM -0500, Steve Fatula wrote:Is there anyway to get an attached serial port working on Debian and raspberry PI 4? It appears the tested installs want to use it as a serial console, I do not. I want to use UART1, the PL011, as an RS232 port to a projector. I can do this using Raspberry OS, but, not Debian using the tested installs. There is no way to disable Bluetooth via the overlays used on Raspberry OS. I can sort of mess around and stop the console from being started on ttyS1, but no way to use the port as a serial port to send and received data. Apparently the dtoverlays are not there. So, is there any way to really use a serial port, attached to any GPIO pins, as a real RS232 port using Debian images? if so, what do I need to disable or enable? As mentioned, had it working on Raspberry OS which is based on Bullseye. But unfortunately I can't use Raspberry OS for our usage.>From what I have read you should be able to enable uart2 through uart5 on the Pi4B using the dts overlays. I don't have a Pi4 yet so no experience with doing that unfortunately. https://forums.raspberrypi.com/viewtopic.php?t=244827 seems to have some talk about it though. I never have used a serial port on a pi, 3 or 4. I'm running an 80 yo Sheldon lathe with a pi4 now but used a pi3 before the 4 came out. My use of a mesa interface card ties up the gpio header as it talks tothe mesa cards at ohmygawd baud rates, sending data to the mesa card in 32 bit packets at 42 megabaud, and getting the reply's back at 25 megabaud, The use of the SPI interface leaves the wired net port open for normal use and my remote operating channel is over its ipv4 address with ssh for terminal services, and sshfs for file transfers.. And running on raspios buster version, it Just Works. other than linuxcnc which needs a realtime kernel as the raspios kernel has been replaced with one I built, right on the pi: pi@rpi4:/media/pi/workspace $ uname -a Linux rpi4.coyote.den 4.19.71-rt24-v7l+ #1 SMP PREEMPT RT Thu Feb 6 07:09:18 EST 2020 armv7l GNU/Linux workspace is a 240gig sata ssd plugged into a usb3 adapter, only about 20x faster than its 64G boot u-sd. Within its speed limits, it can do anything the bigger, more power hungry intels can do. Total power consumption, monitor and all the interfacing is about 22 watts. The lathes 250 supply is controlled by SSR's linuxcnc controls. And the lathe can do tricks that weren't even invented yet when it was new. To an accuracy of about .002 mm. There's lots of things the pi's can do if given the chance to try. Needing a uart to talk to it is not a requirement here. Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis |