Hi, I've been struggling for some time now trying, to get my Onstep to work with Astroberry on a RPi 3B+. I've flashed and updated the latest version of Astroberry, and am running Onstep in the STM32 Blue Pill configuration. When connecting via /dev/ttyUSB0, I get the message '..Port /dev/ttyUSB0.is already used by another driver or process.' I've also been able to connect with WiFi--sort of, as EKOS can sometimes read the local RA/DEC, but nothing else happens. I've found other threads which allude to a problem that this version of the Onstep has using the CP2102 UART to TTL, but I've been unable to wind my way through the threads successfully to a solution (too many trial and error paths leading nowhere that I can follow).
Can someone please guide me through the fixes that I need to implement? I understand that it should be possible, but finding the help has been problematic.

I should note that my OnStep system runs just fine with ASCOM, supporting also PHD2 guiding and camera/mount control through APT on a creaky old PC laptop. I keep telling myself that if I can't get this INDI solution to work, then the RPi becomes either a garage door controller or a paperweight.

Thanks for any assistance

Serial devices IDs are assigned in the connection order i.e. first usb device would be /dev/ttyUSB0, second would be /dev/ttyUSB1 and so on (with some exceptions but I think they do not apply here).
Make sure that you test Onstep having this in mind. Also try testing it without other devices connected to USB. If it works reconnect each device one by one to identify the conflicting device.

Hello,

The magic word I read for me is UART. In ASCOM, the device probably shows up as COMX, where X is a number 1-n. Which port was this used as identified by ASCOM?

If a UART device, I use ttyACM for UART devices. To do this, I create a custom rule to establish ttyACM type ports. First, I use: LSUSB to see what the PI OS has taken in as identification. LSUSB will give the needed idVendor and idProduct values to build a rule.

rnshagam I don't know if you have your setup working right now. I've just finished mine that is working as a charm. I'm using the WiFi addon on OnStep to create a Hotspot at the standard 192.168.0.1 IP. Then I've configured my Astroberry to connect to ONSTEP WiFi network if available, if not it will go back to my home wifi (two different WiFi configurations with higher priority for OnStep do the trick). So when I'm in the field I start OnStep and once it creates its hotspot y boot Astroberry. From this point I've connected PC, iPhones and iPad to the ONSTEP Wifi and all of them can access (via VNC or SSH) the software running on Astroberry.

Thanks, but I've given up with Astroberry for the time being. Been having enough 'fun' just running OnStep off my computer and home network--which I can usually do quite successfully. It seems that my OnStep controller can get finicky about making the home wifi connection, even though I'm fairly knowledgeable about setting it up to talk to wifi routers, etc. ( I think there's an underlying hardware issue that the OnStep developers are unwilling/unable to address with regard to cheap ESP8826 components). As for Astroberry and Rpi's, I don't currently have the patience to acquire and wade through all the Linux skills that I seem to need to know. I'm an old-time Windows user whose programming skills never got much beyond Quick Basic, although I can nose my way through Arduino scripts. I expect that I will give Astroberry another try if I find there's a clear advantage over the ASCOM-based system I'm currently using (PHD2/APT/Cartes du Ciel).

I understand you. We are here to use our telescope, so if you have all your ecosystem working and covering all yor bases, there is not need to look for other system.

Clear Sky!