Hi all,
I've been working with some USB for a bit now.
I have a 64byte array being sent both directions and I simply structure the array with the command for the PIC along with a 'sequence' number so I know the array coming back is the latest data.
A typical command is a byte code that may do something like "get AD input AN0" an return it in the PC's Input array.
I can command the PIC all day long as rapidly as possible but to use a command that expects a return result like an A/D reading, is most often delayed and I have to read the InputBuffer until the sequence number matches the latest command that went out. This results in delays of 100 to 300 msecs before I get the latest result back! I've use some toggling pins to check on the timing and the PIC is only using about 200-300uSecs to finish with its DoUSBIn and then DoUSBOut response. Yet on the PC side there is this delay.
I've tried flushing the USB Buffers among other things and still I get these response delays. I've had this in both my HIDMaker code and in some code that Jan Axelson. has on her site.

Has anyone encountered this phenomenon?