写出完整libusb 异步传输例程,使用多线程读写操作
时间: 2024-10-09 12:04:53 浏览: 29
在libusb库中,异步传输通常通过回调函数和多线程处理来实现。以下是一个简化的Python示例,使用`threading`模块来演示如何在一个单独的线程中进行异步的USB设备读写操作:
```python
import libusb1
import threading
# 初始化libusb context
context = libusb1.USBContext()
def async_transfer(device, endpoint, buffer_size):
def transfer_callback(transferred_bytes, status, error_number):
if status == libusb1.LIBUSB_TRANSFER_COMPLETED:
print(f"Received {transferred_bytes} bytes")
else:
print(f"Transfer failed with error {error_number}")
# 开始异步读取或写入
request_type = libusb1.LIBUSB_REQUEST_TYPE_DIR_IN if writing else libusb1.LIBUSB_REQUEST_TYPE_DIR_OUT
request = libusb1.libusb_fill_transfer(
.transfer_buffer,
device.handle,
endpoint,
buffer_size,
request_type,
transfer_callback,
None,
)
# 开启传输
try:
result = context.queue_transfer(request)
if result > 0:
print("Transfer started...")
else:
print("Failed to queue transfer.")
except Exception as e:
print(f"Error queuing transfer: {str(e)}")
# 设备信息和端点
device_address = ... # 你的设备地址
endpoint = ... # 你想使用的端点(IN或OUT)
buffer_size = ... # 每次请求的数据大小
# 创建读写标志
writing = True # 当True表示写操作,False表示读操作
# 分配内存缓冲区
transfer_buffer = (c_char * buffer_size).from_buffer(bytearray(buffer_size))
# 创建线程处理异步任务
async_thread = threading.Thread(target=async_transfer, args=(device_address, endpoint, buffer_size))
async_thread.start()
# 等待线程完成,可根据需要添加其他线程同步逻辑
async_thread.join()