USB名词解释 and 问题解答（最前）

最新推荐文章于 2024-10-17 23:14:09 发布

转载最新推荐文章于 2024-10-17 23:14:09 发布 · 361 阅读

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原文链接：http://www.cnblogs.com/sunmaoduo/p/3923956.html

本文深入解析了USB技术中的核心概念，包括friendly_name、bcdUSB、bcdDevice、bufferlength等，详细解释了它们的含义及其在USB通信中的作用。

friendly_name
　　是什么意思：

non-endpoint IO method
　　(SetAltIntfc, Open, Reset, etc.)

BCD
　　Binary-Coded Decimal‎，简称BCD，称BCD码或二-十进制代码，亦称二进码十进数. 常见BCD编码有8421BCD码，2421BCD码，余3码.
　　详见：http://baike.baidu.com/subview/179451/12488524.htm?fr=aladdin

bcdUSB
　　USB specification version number (e.g., 0200H for V2.00 )

bcdDevice
　　Device release number in binary-coded decimal

buffer length

endpoint's transfers size
　　Each non-control endpoint has a transfer size that is some multiple of its MaxPktSize. This transfer size can be adjusted programmatically.

　　The transfer size establishes the size of internal buffers used by the USB driver stack for performing data transfers. Larger values for the transfer size enable data transfers involving fewer transactions. However, those larger buffers also consume more available memory.
　　SetXferSize( ) sets the current transfer size setting for the endpoint. It automatically sets the transfer size to a multiple of the endpoint's MaxPktSize property that is greater or equal to the requested xfer size.

MaxPkSize
　　MaxPktSize contains the value indicated by the wMaxPacketSize field of the USB_ENDPOINT_DESCRIPTOR structure that was passed to the endpoint object's constructor.
　　MaxPktSize is calculated by multiplying the low-order 11 bits of wMaxPacketSize by the value represented by 1 + the next 2 bits (bits 11 and 12) .

abstract class
　　abstract class, having a pure virtual method, BeginDataXfer( ). Therefore,instances of it cannot be constructed. CCyControlEndPoint,CCyBulkEndPoint,CCyIsocEndPoint, and CCyInterruptEndPoint are all classes derived from CCyUSBEndPoint（abstract class）.

CreateEvent

void ISR_Sudav(void) interrupt 0

　　interrupt 0 是什么意思：　　

转载于:https://www.cnblogs.com/sunmaoduo/p/3923956.html