Probably not a help...
Hi wayne,
I'm not 100% sure what you are describing so correct me if im wrong..
As I undersatand it, you are sending data from a pic which is recieved by the PC application and then the application sends data back to the pic, and you are seeing the 1 - 15ms difference between the transfers or vice-versa.
If this is correct and from what I have gathered, HID is not an exactly timed data transfer method. The PC will try to service the report request within the time asked for by the device as specified in the descriptors. The pic will only transfer/receive HID data when it has received a in/out report request from the PC.
I had an issue when I made a pic scope, where I could not transfer the data fast enough and got glitches in the waveform displayed in Visual Studio.
I'm not sure what you need to acheive, but it sounds like you may need to look into inturrupt or asyncronous transfer for a more reliable data packet request time.
You can also use ping pong buffering so that data is always ready to be send but I have no idea if PBP handles these - I doubt it does.
I'm not an expert and may not have understood you correctly but I'm sure someone else will come along and help you out.
Paul
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| PBP 2.47/2.50 | MCS+ 3.0.0.5 | U2 Prog | Vista x64 | NO SLEEP!!!!!!! |
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