donw

JM60 USB HID transfer speed

Discussion created by donw on Oct 6, 2008
Latest reply on Oct 8, 2008 by donw
I have the DemoJM60 board, running the CMX USB stack
demo code, patched to echo back 64 byte data packets.
My PC code is Visual Basic 6 running  USBHIDIO.vbp  from lvr.com
which uses the HID driver of XP.
I have now increased the report size to 576 bytes , so on receipt of  a transaction from the PC
the micro sends 9 transactions (of 64bytes).
This has decreased the total transfer time (mostly due to less OUT transactions from the PC, I guess)
so I now get 2MByte of data to the PC in 130seconds. This is still very slow.
Does anyone have a (compiled) Visual C program which sends (anything) & recieves data transaction using the HID driver,  just to see if Visual Basic is part of the speed problem?

My other thought:
Reading between the lines on USB transfers, I get the impression that multiple EndPoints data packets
can/are send in the same transaction (ie the 1 msec blocks). Hence if I have 2 (or more ) endpoints running I would double the transfer speed.
Is this idea correct?
Does anyone have the micro code for added another endpoint to the CMX demo code? It is
way beond my limited C coding ability!...

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