BPI-R2 + ch341 serial adapter = not work

dimap101 · February 11, 2020, 1:41pm

Hi !

has anyone tried using a serial adapter on CH341 (USB - RS485) ? This adapter recognise by kernel, but not working ((( In Windows this adapter work fine.

dmesg output: [72004.731453] usb 3-1: new full-speed USB device number 2 using xhci-mtk [72004.893011] ch341 3-1:1.0: ch341-uart converter detected [72004.902875] usb 3-1: ch341-uart converter now attached to ttyUSB0

lsusb output: Bus 003 Device 002: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter

uname -a output: Linux bpi-iot-ros-ai 4.4.70-BPI-R2-Kernel #4 SMP Thu Mar 29 10:31:30 CST 2018 armv7l armv7l armv7l GNU/Linux

I find some information about this promblem - https://forums.linuxmint.com/viewtopic.php?t=230835 How I can change and recomplile CH341 module ?

dimap101

dimap101 · February 11, 2020, 1:54pm

Latest CH341 module source http://www.wch.cn/download/ch341ser_linux_zip.html

frank-w · February 11, 2020, 4:16pm

Kernelsource for your current kernel: https://github.com/BPI-SINOVOIP/BPI-R2-bsp

But i don’t think you can get the driver working because kernel is 4 years old. You can try newer one (e.g. 5.4) from my repo and include driver there if it’s not already there

Newer kernels from 2007+ (2.6.24 ) seem to contain driver for this chip

dimap101 · February 15, 2020, 10:11am

Thank you for answer. Right now, I’m not sure if the problem is in the ch341 driver. I changed the USB-RS485 adapter to new ones (FT232RL), but it still doesn’t work. Under Windows 10, the new adapter also works well.

frank-w · February 15, 2020, 10:29am

My kernels (and maybe odficial too) do not contain drivers for usb2serial devices yet…

Just to be sure…You want to use usb-side on r2 or serial side (for get debug-console)?

dimap101 · February 15, 2020, 10:50am

I want use USB side on R2. I need connect RS485 device to R2.

USB device both adapter (ch341 and FT232RL/FTDI) discovered correctly and visible. Device file /dev/ttyUSB0 is present when adapter connected.

frank-w · February 15, 2020, 11:04am

Ok,then you need kernel with matching driver installed on r2…

dimap101 · February 15, 2020, 11:27am

I check kernel configuration in BSP - USB serial driver included (CH341 and FDTI also included).

frank-w · February 15, 2020, 11:40am

Are other usb-devices recognized (e.g. storage) on same port? Do you see your usb2serial in lsusb? Look in dmesg if anything happens when you connect your device

dmesg -w

Or look if there is anything related in syslog

grep -i 'usb' /var/log/syslog

dimap101 · February 15, 2020, 11:48am

dmesg -w | grep serial

[ 13.057814] usbcore: registered new interface driver usbserial

[ 13.057890] usbcore: registered new interface driver usbserial_generic

[ 13.057954] usbserial: USB Serial support registered for generic

[ 13.079165] usbserial: USB Serial support registered for FTDI USB Serial Device

dimap101 · February 15, 2020, 11:50am

lsusb | grep serial

Bus 003 Device 002: ID 0403:6001 Future Technology Devices International, Ltd FT232 USB-Serial (UART) IC

frank-w · February 15, 2020, 12:07pm

Looks good…and no /dev/ttyUSBx?

dimap101 · February 15, 2020, 12:09pm

/dev/ttyUSB0 is present. But not receive data from RS485… Tomorкow I try connect Windows 10 terminal via RS485 to R2 terminal.

frank-w · February 15, 2020, 12:11pm

Maybe you need to configure serial port (baudrate,stopbits,…)

dimap101 · February 15, 2020, 12:13pm

send/receive data by bash script:

#!/bin/sh

cmd=echo -n "x00x01x01x01x01x01x01x01x01x77x81" | sed 's/x/\\\0x/g'

port=“ttyUSB0”

ans="./1"

stty -F /dev/$port 9600 -cstopb -oddp -opost raw

echo -n $cmd | awk -F’’ ‘{for(i=1; i<=NF; i++) {printf “%c”, $i}}’ > /dev/$port & ( dd if=/dev/$port of=$ans count=128 ) & sleep 10 ; kill $!