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FX3: Control center question | Cypress Semiconductor

FX3: Control center question

Summary: 1 Reply, Latest post by HKRA on 04 Jul 2013 10:25 PM PDT
Verified Answers: 0
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zulunation's picture
13 posts

 I'm using control center with FX3 chip. The  bulkloop firmware is loaded.

I send one byte. After that i send another byte. When i read pipe i get the first byte. Then i read again and get the second byte.

I can't understand how cotrol center knows that only one byte must be read from the pipe. And another one byte must be read the second time.

When using DeviceIOcontrol we must specify the number of bytes to read. How control center knows hom many bytes are in the pipe?


hkra's picture
Cypress Employee
12 posts


When the transfer size is less than the USB packet(1024 for USB3.0) it is considered as a short packet and inside FX3 the buffer gets committed.

In the bulkloop example when you are sending two consecutive 1 bytes of data inside FX3 2 dma buffers are getting commited. So while doing the IN transfer each buffer is sent out separately and you are seeing the described behaviour.



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