# ROS-STM32 communication

[TOC]

## USB轉串口模塊
常見的有：CH340，CP2102
we use PL2303 USB to TTL（手邊剛好有）
linux:
一般情況不須另外安裝驅動程式，若需要請查看下面文章：
https://www.796t.com/content/1541534290.html

1. 利用下面指令確認是否已有驅動程式支援：

$ lsmod |grep pl2303


若有驅動程式，會得到類似的資訊。

2. 檢視系統資訊：

$ dmesg | tail -f

由上面結果可以看到裝置為ttyUSB0

3. 尋找serial port的資訊

udevadm info -a -n /dev/ttyUSB0
udevadm info -a -n /dev/ttyUSB1
udevadm info -a -n /dev/ttyUSB2



4. 利用上述資訊創建自定義的rules
rules名字自己取

$ sudo vim /etc/udev/rules.d/rplidar_imu_stm32_port.rules 

In the file:

KERNEL=="ttyUSB*", ATTRS{devpath}=="3.3", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", MODE:="0777", SYMLINK+="front_left_laser"
KERNEL=="ttyUSB*", ATTRS{devpath}=="3.2", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", MODE:="0777", SYMLINK+="back_right_laser"
KERNEL=="ttyUSB*", ATTRS{devpath}=="3.1", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60",, MODE:="0777", SYMLINK+="imu"
~                                                                                                                                                                                                                                   
~                                                                                                                                             

# KERNEL=="ttyUSB*"： 把所有的ttyUSB都叫出來修改,並符合後面條件的都叫出來修改。
# MODE:="0777": MODE代表賦予串口端口的權限，"0777"是具體的權限
# ATTRS{devpath}：用來使用在當廠商代碼跟商品代碼都一樣時,這個通常是電腦本身的port口的號碼,除此之外,如果像我們有另外接usb集線器就有可能會有"."。
# ATTRS{idVendor}：廠商代碼,有可能rpli imu這類的都會有一樣的名字。
# ATTRS{idProduct}: 商品代碼,有可能rpli imu這類的都會有一樣的名字,因為通訊的東西都一樣。
# SYMLINK+="stm32_port": 別名，"stm32_port" 是自己取的別名
:warning: 通常devpath都是選第一次出現的devpath因為在那裡才有標明確切在集線器的位置。
4. 重新加載udev規則

＄ service udev reload
＄ service udev restart

5. 拔插USB之後，查詢更改結果

 ls -l /dev/ | grep ttyUSB


結果類似截圖，則表示更改完成！

https://leidawt.github.io/post/%E5%9C%A8stm32%E4%B8%8A%E8%BF%90%E8%A1%8Cros%E8%8A%82%E7%82%B9-rosserial-stm32%E5%BC%80%E5%8F%91%E5%8F%8A%E8%B0%83%E8%AF%95%E6%96%B9%E6%B3%95/

## rosserial (failed)
主要按照第二個連結影片步驟：
https://blog.csdn.net/leida_wt/article/details/109690562

https://www.bilibili.com/s/video/BV19B4y1M7f3
安裝rosserial_stm, 修改stm32cubeIDE程式碼, 執行
但最後rosrun時, reqiring topic失敗


## 07/28 問學長方法
1. 利用screen /dev/ttyUSB0 115200 (在terminal)，先確認STM32是否有正確傳送訊息
2. 之後在ros寫node：建議用pyserial
https://pyserial.readthedocs.io/en/latest/shortintro.html

:::info
$ screen /dev/ttyUSB0 9600 (usb port and baud)
* Close screen:
ctrl+a -> K -> y
:::
目前問題：
* linux terminal screen ttyUSB0 沒有訊息
* 改成 screen ttyACM0 才出現訊息
* STM32 Debug Console 新增ttyACM0也可以查看
* ttyACM0 是 STM32 micro usb 傳輸線
* ttyUSB0 是 uart 傳輸線訊息

解決：
* 把 uart2 換成 uart3 pin 則可以成功傳送

## Linux terminal command <-> STM32
### STM32 Send Message
In STM32CubeIDE:
1. Connectivity: USART3
2. Mode: Asynchronous
3. Baud rate: 115200
4. Code in while loop:

HAL_UART_Transmit(&huart3, (uint8_t*)"Hello World!\n\r", sizeof("Hello World!\n\r")-1, 1000);
HAL_Delay(200);

5. Run

In Linux terminal:
1. find Uart port

$ ls -l /dev/ttyUSB*

2. screen the message STM32 sending

$ screen /dev/ttyUSB4 115200


3. close screen

ctrl+a -> K -> y

### STM32 Receive message
In STM32CubeIDE:
1. Connectivity: USART3
2. Mode: Asynchronous
3. Baud rate: 115200
4. Code in Private user code:

uint8_t Rx_data[10];

6. Code in while loop:

HAL_UART_Receive(&huart3, Rx_data, 10, 100);

5. Debug
6. Llive Expression
7. Add New Expression: Rx_data
8. Resume

In Linux terminal:
1. Set baud rate

$ stty -F /dev/ttyUSB0 115200

2. Write message to the uart

$ echo "Helloworld" > /dev/ttyUSB0


## Pyserial
### install

$ sudo apt-get install python3
$ sudo apt install python3-pip
$ sudo pip3 install pyserial
$ python3 -m pip show pyserial


$ mkdir pyserial_ws
$ cd pyserial_ws
$ touch receive.py
$ vim receive.py

In the file:

import serial
ser = serial.Serial()
ser.port = '/dev/ttyUSB0'
ser.baudrate = 115200
ser.open()
while(True):
    line = ser.readline()
    print(line)

$ python receive.py


## keyboard control stm32 motors
### Method 1:
teleop_twist_keyboard + base_controller

teleop_twist_keyboard:
https://github.com/ros-teleop/teleop_twist_keyboard

base_controller:
subscribe data type: geometry_msgs.msg / Twist

### Method 2: (目前執行方案)
import keyboard + keyboard_control

keyboard_control:
subscribe data type: std_msgs.msg / String

**Github file:**
Ros: https://github.com/PeiChi-Hu/unmanned_car_KeyboardUartToSTM32
keyboard_control pkg & base_controller pkg

STM32: https://github.com/PeiChi-Hu/unmanned_car_stm/tree/main/keyboard0805

terminal 1:

$ roscore

terminal 2:

$ source /opt/ros/noetic/setup.bash
$ source ~/stm32_ws/devel/setup.bash
$ rosrun base_controller keyboard_control.py

terminal 3:

$ sudo su (enter root)
$ source devel/setup.bash (in workspace directory)
$ rosrun keyboard_control keyboard_control.py
$ exit  // exit root

Use command sudo su to enter root, because python keyboard import function requires root.

:small_red_triangle:try to find some other ways to avoid root reqiurement.
### Method 3:
import getkey + keyboard_control

getkey function:
:small_red_triangle: Issue: getkey(blocking=False) results in missed keyboard inputs
https://github.com/kcsaff/getkey/issues/17

getkey(blocking=True):
The keyboard status will remain until the next input.
-> need to modify the STM32 code.
:small_red_triangle:STM32 code: in the dc motor function, we put stop function at the end. However, the car didn't move.

### Method 4:

import pynput + keyboard_control

:small_red_triangle:Problem: pynput do not detect the keyboard inputs

### Method 5:

import tkinker + keyboard_control

tkinker: GUI module in python