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FT232H Virtual com port driver problem

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Anatolii:
Hi all.

I make my some application from MCU in the CPU style FIFO mode i send data to computer.

MCU generate flow 512 bytes, pause 20-30ms and again.

From computer i fetch data amount in the RX buffer and when collect 512bytes copy it to my data massive. When collect control amount 64k-100mb close connection and start another task which check data.

But happens strange thing. After pause computer stable receive packets 53, 1, 458 bytes. And same stable lost frames of data. If send short block less 53 bytes works well. If make like request 512 bytes, receive 512 bytes also works, but slow around 0.5mb/s.
MCU TMS320F28379D, in the normal operation can`t send singe byte (but possible simulate in the s/w mode) just pairs of bytes.

Then I rework all, to D2XX_NET and 245 async mode, after 2 days of manipulation with code it send to computer up to 10mb/s in any sequence. Any transfer block size, even uninterrupted by MCU DMA. Even if WAIT signal keep unconnected, in this case speed increase up to 10mb/s from 8,6mb/s. Even with abnormal short EMIF setup, hold and strobe signals. I take stable flow and opposite try find where it fault.

But what wrong with VCP? Is possible in VCP mode send big amount of data? Is possible say FT232H do not send packet until collect full frame 512 bytes? I really tired, 2 weeks of not sucsess experiments.
Works well with Visual studio, but main project in the Matlab where haven`t D2XX support.

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