sorry for cluttering this forum with my "data". Forget the last two reports.
The reason for this strange behaviour is that there are CRC errors on the USB bus which are not detected in the case of high speed. In full speed they are passed to my driver and my driver takes the last valid measurement. In high speed however, my driver doesn't get the CRC error from the usb-core and therefore the sine wave looks a bit "dented". :-)
I'll look into the CRC detection in high speed.
/Bernd
Bernd Porr wrote:
Hi all, again,
some more data to add:
I've also run an acquisition with double buffering (high speed, 2.6.2-rc3). There's another pattern:
1 -0.687168 2 -0.157038 3 0.119029 4 0.401098 * 5 0.685167 6 0.401098 * 7 0.973238 8 1.255306 9 1.533374 * 10 1.801440 11 1.533374 * 12 2.059503 13 2.299561 14 2.521616 * 15 2.721664 16 2.521616 * 17 2.895707 18 3.041743 19 3.161772
Again, the input signal is a sine. Every number is a usb frame with data behind here.
My driver? The ISO patch?
/Bernd
Bernd Porr wrote:
This seems to be a new problem.
ISO transfer, quad buffering (4 URBs), high speed:
I suspect that I get old data from one of the four 4 urbs in the completion handler. As some of you know I do data acquision via the usb. The data is a sine wave in this case. It looks like that:
1 -0.891218 2 -1.175287 3 -0.281069 4 -1.445353 * 5 -1.691413 6 -1.913467 7 -2.111516 8 -1.445353 * 9 -2.271555 % 10 -2.403587 11 -2.499610 12 -2.561625 13 -2.271555 % 14 -2.585631 & 15 -2.577629 16 -2.531618 17 -2.453599 18 -2.585631 &
The first number is the usb frame and the second one the data. I've marked the data which is the same. I do quad buffering and there's a strange repetition of the data which happens every 4 ms.
The firmware code is the same for high- and full speed. In the driver also the same code is used for high- and full speed.
In full speed it looks different:
1 2.503611 2 2.909710 * 3 2.909710 * 4 3.243792 & 5 3.243792 & 6 3.505856 7 3.505856 8 3.675897 9 3.675897 10 3.755917 11 3.755917 12 3.747915 13 3.747915 14 3.649891 15 3.649891 16 3.473848 17 3.473848 18 3.221787 19 3.221787 20 2.907710
In this case the adjacent data is doubled.
This all might be a problem of my driver but its funny that I get two different patterns of data through the same driver/firmware code.
/Bernd
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