jeston orin nx--python程序编写中所遇到的问题集合

一、串口权限不够

报错信息：

serial.serialutil.SerialException: [Errno 13] could not open port /dev/ttyACM0: [Errno 13] Permission denied: '/dev/ttyACM0'

1. 临时解决方案（快速验证）： 

# 临时赋予设备读写权限（重启后失效）
sudo chmod 666 /dev/ttyACM0

2. 永久解决方案（推荐）：

# 将当前用户加入 dialout 用户组
sudo usermod -aG dialout $USER

# 配置 udev 规则（需要重启生效）
echo 'KERNEL=="ttyACM*", MODE="0666"' | sudo tee /etc/udev/rules.d/50-ttyACM.rules

# 强制刷新 udev 规则
sudo udevadm control --reload-rules
sudo udevadm trigger

二、Ubuntu 22.04中ch34x串口无法使用的问题

1、问题描述：

        使用lsusb命令可以看到有Bus 001 Device 005: ID 1a86:7523 QinHeng Electronics CH340 serial converter是能识别出ch34x设备

2、解决方案：

 step1：WCH官网下载最新的驱动CH341SER_LINUX.ZIP  

step2：解压驱动

        unzip CH341SER_LINUX_ZIP 得到三个文件ch34x.c Makefile readme.txt

step3：编译安装驱动      

        eadme.txt里面介绍到驱动的加载方式，但注意到第7行写着支持的内核版本从2.6.25 to 3.13.x隐约感觉问题不妙，敲入make命令后，果然出现了错误(这年头官网的驱动也不靠谱哇)

make -C /lib/modules/5.15.0-58-generic/build  M=/home/$USER/Documents/CH341SER_LINUX  
make[1]: Entering directory '/usr/src/linux-headers-5.15.0-58-generic'
  CC [M]  /home/$USER/Documents/CH341SER_LINUX/ch34x.o
/home/$USER/Documents/CH341SER_LINUX/ch34x.c: In function ‘ch34x_close’:
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:591:9: error: unknown type name ‘wait_queue_t’; did you mean ‘wait_event’?
  591 |         wait_queue_t wait;
      |         ^~~~~~~~~~~~
      |         wait_event
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:591:22: warning: unused variable ‘wait’ [-Wunused-variable]
  591 |         wait_queue_t wait;
      |                      ^~~~
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:590:14: warning: unused variable ‘timeout’ [-Wunused-variable]
  590 |         long timeout;
      |              ^~~~~~~
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:589:13: warning: unused variable ‘bps’ [-Wunused-variable]
  589 |         int bps;
      |             ^~~
/home/$USER/Documents/CH341SER_LINUX/ch34x.c: At top level:
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:1297:27: error: initialization of ‘unsigned int (*)(struct tty_struct *)’ from incompatible pointer type ‘int (*)(struct tty_struct *)’ [-Werror=incompatible-pointer-types]
 1297 |         .write_room     = ch34x_write_room,
      |                           ^~~~~~~~~~~~~~~~
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:1297:27: note: (near initialization for ‘ch34x_device.write_room’)
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:1298:28: error: initialization of ‘unsigned int (*)(struct tty_struct *)’ from incompatible pointer type ‘int (*)(struct tty_struct *)’ [-Werror=incompatible-pointer-types]
 1298 |         .chars_in_buffer = ch34x_chars_in_buffer,
      |                            ^~~~~~~~~~~~~~~~~~~~~
/home/$USER/Documents/CH341SER_LINUX/ch34x.c:1298:28: note: (near initialization for ‘ch34x_device.chars_in_buffer’)
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:297: /home/$USER/Documents/CH341SER_LINUX/ch34x.o] Error 1
make[1]: *** [Makefile:1902: /home/$USER/Documents/CH341SER_LINUX] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.15.0-58-generic'
make: *** [Makefile:5: default] Error 2

  uname -r 可查看操作系统的发行版号，获得Ubuntu22.04的Linux版本是5.15.0-58-generic
        在Linux kernel source code v5.15查看ch341.c的源代码，直接复制到CH341SER_LINUX/ch34x.c中，重新make，此次通过。
        在目录执行sudo make load命令，出现以下错误

modprobe usbserial
insmod ch34x.ko
insmod: ERROR: could not insert module ch34x.ko: File exists
make: *** [Makefile:10: load] Error 1

        将目录中生成ch34x.ko文件复制到/lib/modules/$(uname-r)/kernel/drivers/usb/serial下，使用lsmod查看模块，发现已识别。

终端输入以下指令，可以直接打开/lib/modules/$(uname-r)/kernel/drivers/usb/serial：

sudo xdg-open /lib/modules/5.15.148-tegra/kernel/drivers/usb/serial

Module                  Size  Used by
ch34x                  24576  0
usbserial              57344  1 ch34x

step4测试

        正常到达这步就可以与开发板通信了，但是配置完minicom后minicom: cannot open /dev/ttyUSB0: No such file or directory
        这时查看/dev/ttyUSB*发现没有此文件

zsh: no matches found: /dev/ttyUSB*

        使用dmesg查找原因sudo dmesg | grep tty

[    0.223411] printk: console [tty0] enabled
[   44.099146] usb 1-1: ch341-uart converter now attached to ttyUSB0
[   44.673749] usb 1-1: usbfs: interface 0 claimed by ch34x while 'brltty' sets config #1
[   44.675063] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0

        这里出现了brltty进程，通过官网得知：

BRLTTY is a background process (daemon) providing access to the Linux/Unix console (when in text mode) for a blind person using a refreshable braille display.
brltty是一个后台进程（守护进程），为盲人提供对Linux/Unix控制台的访问（当处于文本模式时），使用可刷新盲文显示。

        直接删除sudo apt remove brltty

        重新连接开发板ls /dev/ttyUSB*这时已经出现了/dev/ttyUSB0这个设备！！！
此时sudo minicom -c on可正常使用minicom与开发板进行通信

报错3：usb权限不足

报错信息：