怎么使用CyAPI进行慢帧时间

使应用程序正确地与硬件对话。（我有一些怪癖，但我现在不是在追赶那些），因为帧定时，我们从另一个USB解决方案切换到高速设备。整个系统的数据速率非常低（大多数数据包一次只有几个字节，而不是频繁的），但是全速解决方案不起作用。通过设备（DavasyCARD），系统的延迟比旧ISA接口慢10-20倍。当我看公共汽车定时时，车架是4ms。
我研究了帧定时，发现高速应该具有125US子帧。有了这样的定时，我应该能够使系统的工作速度与ISA相同，可能有几个非关键区域稍慢一点。
在初始化代码中，软件通过外部机箱中的256个可能地址的范围来发送和接收一个字节（它正在寻找什么硬件安装在机箱中）。它在一个紧密的循环中，当使用ISA卡时，每个I/O调用大约有15个U。这不是程序的一个关键部分，我把它当做是比较接口之间的时序（IPLAN最终将轮询移动到固件，只读取一个批量传输中的所有256个字节，但这是第二阶段）。
用逻辑分析仪查看流量，我看到每笔交易时间为3-4MS，而不是125US。什么会导致时间比预期慢24到32倍？有趣的是，总线定时几乎与我所看到的全速装置相同，我们拒绝了。
我现在通过控制端点传输来做所有I/O。很多时候需要写几个字节，然后立即读取一两个字节。控制端点的双向性使我能够将这些组合成一个USB调用。
是什么引起了这个问题，我该如何解决呢？
比尔



     以下为原文
  I managed to get the application talking to the hardware somewhat correctly.  (I have a few quirks, but I'm not chasing those right now.)  We switched direction from another USB solution to a high speed device because of the frame timing.  The system has very low data rates overall (most packets are only a few bytes at a time and not that frequent), but a full speed solution was not working.  With the device I tested (DevaSys card), the delays in the system were 10-20 times slower than with the old ISA interface.  Whe I looked at bus timing, the frames were 4ms.
    I researched frame timing and found that high speed is supposed to have 125us subframes.  With that kind of timing, I should be able to get the system working about the same speeds as ISA with possibly a few non-critical areas being a little slower.
    In the initialization code the software does a send and recieve of one byte through a range of 256 possible addresses in the external chassis (it's looking to see what hardware is installed in the chassis).  It does this in a tight for loop that has about 15 us per I/O call when using the ISA card.  This is not a critical part of the program and I left it as is to compare timing between interfaces (I plan to move the polling to firmware eventually and just read all 256 bytes in one Bulk transfer, but that's phase II).
    Looking at the traffic with a logic analyzer, I'm seeing per transaction timings of 3-4ms, not 125us.  What could be causing the timing to be 24-32 times slower than expected?  I find it interesting that the bus timing is almost identical to what I saw with the full speed device we rejected.
    I am doing all I/O via control endpoint transfers at the moment.  Many times I need to write a couple of bytes and then immediately read one or two.  The bidirectionality of the control endpoint enables me to combine these into one USB call.
    What is causing this and how to I fix it?
    Bill