Hello!
My carrier board has RS485 and RS232 transceivers connected to a UART-USB chip, connected to a USB hub that is finally connected to the USB Host pins of the SoM. I have a USB connector hooked to the USB hub as well.
So, when i run lsusb, I see
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
If I connect something to the USB Connector and run again lsusb I can see it listed on the output as well as in /dev/. The RS485 and RS232 chips I cannot see, though. How can I see where they are?
Best,
Jaime
Hi, @jeremias.tx
So, turns out I was testing with a hardware variant that had no ftdi and uart chips mounted (shame on me).
After getting the right hardware, I ran again lsusb and it does show the ftdi chip:
Bus 001 Device 003: ID 0403:6011 Future Technology Devices International, Ltd FT4232H Quad HS USB-UART/FIFO IC
Bus 001 Device 002: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Also, dmesg showed me this:
[ 13.268835] usbserial: USB Serial support registered for FTDI USB Serial Device
[ 13.268966] ftdi_sio 1-1.4:1.0: FTDI USB Serial Device converter detected
[ 13.269077] usb 1-1.4: Detected FT4232H
[ 13.270343] Starting...
[ 13.392086] usb 1-1.4: FTDI USB Serial Device converter now attached to ttyUSB0
[ 13.392248] ftdi_sio 1-1.4:1.1: FTDI USB Serial Device converter detected
[ 13.392352] usb 1-1.4: Detected FT4232H
[ 13.445218] usb 1-1.4: FTDI USB Serial Device converter now attached to ttyUSB1
[ 13.445402] ftdi_sio 1-1.4:1.2: FTDI USB Serial Device converter detected
[ 13.445526] usb 1-1.4: Detected FT4232H
[ 13.503895] usb 1-1.4: FTDI USB Serial Device converter now attached to ttyUSB2
[ 13.504060] ftdi_sio 1-1.4:1.3: FTDI USB Serial Device converter detected
[ 13.504162] usb 1-1.4: Detected FT4232H
[ 13.529392] usb 1-1.4: FTDI USB Serial Device converter now attached to ttyUSB3
So, would it be safe to assume that each ttyUSB* corresponds to each of the 4 uart buses on the ftdi chip?
Best,
Jaime
A bit of an update:
I tried debugging my app, but got an error regarding not having permission to open port ttyUSB1. I have added dialout and gpio to user torizon. Is there other group must I add to this command?
Best,
Jaime
Glad you were able to resolve the UART chip detection over USB. Also yes it’s safe to assume those ttyUART* devices belong to your chip. Typically this is how UART gets enumerated when connected over USB.
As for permission, typically the dialout group includes all UART/tty* devices. So this is surprising to me. Have you made sure to add /dev/ttyUSB1 as a device to the container?
Furthermore can you try running as root and access the device that way? If you can access it as root then at least there’s no issues with access other than permissions.
I’ll check with the team perhaps we forget to include ttyUSB devices as part of our dialout group on Torizon.
Best Regards,
Jeremias
I forgot to add /dev/ttyUSB1 as a device to the container.
Thanks!
Best,
Jaime
Great glad were were able to sort this all out!
Best Regards,
Jeremias
Hi @jaimeibk,
There’s a lot of potential areas here where a failure or series of failure could lead to the transceivers not being detected/read correctly.
As you stated the USB Hub is seen as well as things connected to the traditional USB connector. Therefore I think we can eliminate the USB hub as being a source of issue for now.
I have a couple of thoughts here so let me run through them briefly.
First of all I’m not certain that the UART chips would show up in lsusb. Could you check strictly /dev, typically serial/uart type devices show up in /dev as tty*. Try reconnecting the chips and see if there’s any change/new entries. Also while you’re reconnecting run dmesg before and after you change connections to see if the device detects anything at all.
It may also be the case that additional device tree changes/software changes are needed to properly detect and utilize this additional hardware. But again I’m not certain of this, so try the above checks first so we can gain more information.
Best Regards,
Jeremias
