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| All these API functions have some parameters to set: Timeout, BufferSize and others. |
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All these functions use a synchronous version for the data transfer (Cypress XferData() function). They perform synchronous (i.e. blocking) I/O operations and do not return until the transaction completes or the endpoint TimeOut has elapsed. A synchronous operation (aka blocking operation) is an operation that owns (in an exclusive way) resources and CPU until its job is done. A synchronous function monopolizes resources until its end, even during idle time.
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The API uses the synchronous version because it is more suitable to be included in a DLL and it is already fast. With synchronous version, the API functions are simpler to use.
BufferSize is the size of the buffer used in data/command transmission/reception of a single endpoint; the total buffer size is the sum of BufferSize of every endpoint used.
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See Data Transfer Throughput Optimization for some insights into this kind of influence.
PacketSize
PacketSize is the size of packets used in data/command transmission/reception of a single endpoint.
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Timeout is the time that is allowed to the function for sending/receiving the data packet passed to the function; this timeout shall be large enough to allow the data/command transmission/reception. Otherwise the transmission/reception will fail.
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These values have been verified for a Core i7 processor at 2.20 GHz with Microsoft Windows 7. Other configuration may require others value. An AMD Athlon II at 1.30 GHz with Microsoft Windows 7 might require much (e.g. two or three times) larger values. If your host computer is not highly responsive, you should set TimeOut to even larger values : e.g 20, 50, 200, 1000 ms (the less responsive the host computer is, the higher the recommended values shall be).
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