本文主要是介绍Interrupt Transfers，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
本文转载至: http://www.keil.com/pack/doc/mw/USB/html/_u_s_b__interrupt__transfers.html
Interrupt Transfers have a limited latency to or from a device. In USB, an Interrupt Transfer, or Interrupt Pipe, has a defined polling rate between:
- 1ms and 255ms for full and low-speed
- 125μs to 4096ms for high-speed endpoints.
The maximum packet size for the interrupt endpoint data is:
- 64 or less bytes for full-speed
- 1024 or less bytes for high-speed
The developer can define how often the host can request a data transfer from the device.
For example, for a mouse, a data transfer rate at every 10 ms can be guaranteed. However, defining the polling rate does not guarantee that data will be transferred every 10 ms, but rather that the transaction will occur somewhere within the tenth frame. For this reason, a certain amount of timing jitter is inherent in an USB transaction.
Typically, Interrupt Transfer data consists of event notifications, characters, or coordinates from a pointing device.
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