树莓派通过串口终端访问hidraw设备失败，寻求技术帮助

• 设备通过USB连接，识别为/dev/hidraw0
• 使用hidapi库无法建立通信，仅能通过GTKterm配置/dev/hidraw0实现读写
• 尝试用pyserial编写串口终端程序，连接/dev/hidraw0时提示语法错误
• 已尝试通过Udev修改设备读写权限并加入plugdev组，问题仍未解决

附上尝试的代码：

import tkinter as tk
import serial
import binascii

def send_data():
    data = input_entry.get().strip()
    if data:
        hex_data = data.replace(" ", "").strip()
        byte_data = binascii.unhexlify(hex_data)
        serial_port.write(byte_data)
        display_sent_data(hex_data)

def display_sent_data(data):
    sent_data_text.insert(tk.END, data + "\n")

def read_data():
    data = serial_port.read_all()
    if data:
        hex_data = binascii.hexlify(data).decode()
        display_received_data(hex_data)

def display_received_data(data):
    received_data_text.insert(tk.END, data + "\n")
    # Scroll to the end of the received data text
    received_data_text.see(tk.END)

# Serial port configuration
serial_port = serial.Serial('/dev/ttyUSB1', baudrate=38400, timeout=0.1)  # Replace with your actual serial port configuration

# GUI setup
window = tk.Tk()
window.title("Serial Terminal")
window.geometry("400x300")

# Input entry and send button
input_entry = tk.Entry(window, width=30)
input_entry.pack(pady=10)
send_button = tk.Button(window, text="Send", command=send_data)
send_button.pack()

# Sent data display
sent_data_text = tk.Text(window, height=8, width=40)
sent_data_text.pack(pady=10)

# Received data display
received_data_text = tk.Text(window, height=8, width=40)
received_data_text.pack()

# Read data from serial port
def read_serial():
    read_data()
    window.after(100, read_serial)

read_serial()
window.mainloop()

问题分析与解决方法 #

核心问题 #

pyserial是为串口设备（如ttyUSB、ttyACM）设计的，/dev/hidraw0属于HID类设备的原始字符设备，不属于串口范畴，直接用serial.Serial()打开必然报错。

解决方案1：改用hidapi-python库实现通信 #

GTKterm能正常操作说明设备HID通信逻辑正常，之前hidapi使用失败大概率是参数或调用方式错误。

1. 先安装依赖：

pip install hidapi

2. 修改后的适配代码：

import tkinter as tk
import hid
import binascii

# 替换为你的设备VID和PID（用lsusb命令可查看）
VID = 0xXXXX
PID = 0xYYYY

def open_hid_device():
    try:
        dev = hid.device()
        dev.open(VID, PID)
        dev.set_nonblocking(True)
        return dev
    except Exception as e:
        print(f"设备打开失败: {e}")
        return None

hid_device = open_hid_device()

def send_data():
    data = input_entry.get().strip()
    if data and hid_device:
        hex_data = data.replace(" ", "").strip()
        # 多数HID设备需要前缀报告ID（通常为0x00，需根据设备调整）
        byte_data = b'\x00' + binascii.unhexlify(hex_data)
        try:
            hid_device.write(byte_data)
            display_sent_data(hex_data)
        except Exception as e:
            print(f"发送失败: {e}")

def read_data():
    if hid_device:
        try:
            # 读取64字节（HID默认报告长度，按需调整）
            data = hid_device.read(64)
            if data:
                # 去掉前缀的报告ID（如果设备返回的数据包包含）
                hex_data = binascii.hexlify(data[1:]).decode() if len(data) >1 else binascii.hexlify(data).decode()
                display_received_data(hex_data)
        except Exception as e:
            print(f"读取失败: {e}")

# 以下GUI部分与原代码一致，省略重复内容
window = tk.Tk()
window.title("HID Terminal")
window.geometry("400x300")

input_entry = tk.Entry(window, width=30)
input_entry.pack(pady=10)
send_button = tk.Button(window, text="Send", command=send_data)
send_button.pack()

sent_data_text = tk.Text(window, height=8, width=40)
sent_data_text.pack(pady=10)

received_data_text = tk.Text(window, height=8, width=40)
received_data_text.pack()

def read_loop():
    read_data()
    window.after(100, read_loop)

read_loop()
window.mainloop()

解决方案2：直接通过文件操作读写hidraw #

如果不想用hidapi库，可以模拟GTKterm的原生文件操作方式：

修改原代码的串口配置与读写函数：

# 打开hidraw设备
hidraw_fd = open('/dev/hidraw0', 'rb+')

def send_data():
    data = input_entry.get().strip()
    if data:
        hex_data = data.replace(" ", "").strip()
        byte_data = binascii.unhexlify(hex_data)
        hidraw_fd.write(byte_data)
        hidraw_fd.flush()
        display_sent_data(hex_data)

def read_data():
    data = hidraw_fd.read(64)
    if data:
        hex_data = binascii.hexlify(data).decode()
        display_received_data(hex_data)

额外排查步骤 #

1. 用lsusb确认设备的VID/PID，确保hidapi调用参数正确
2. 用cat /dev/hidraw0和echo -n -e '\xXX\xYY' > /dev/hidraw0测试原生读写，验证设备是否响应
3. 查看GTKterm的配置细节，确认是否使用了特定报告ID或数据格式，同步到代码中

内容的提问来源于stack exchange，提问作者Trynabal