I have a Cypress FX2 based USB interface board connected to our radar data
acquisition chassis. It is used for configuring the hardware and getting data
back to the PC.
I wrote a driver which is a very skinny wrapper around the (very handy)
usb_fifo device node code.
I have several end points, all bulk. 2 are for serial comms, 2 for a low speed
control bus and 1 for high speed data back to the PC.
The PC sends 10-250 byte packets out to modules on the serial bus and gets
replies (after a 10-500 msec) of a similar size.
The low speed control bus is driven by the FX2 and the PC sends it 3 byte
packets which is processes to read/write on the control bus, then sends a 3
byte packet back.
I find that my application has rare problems where it does not get a reply from
the micro to a control bus packet, or perhaps the micro doesn't receive it (I
need to add a sequence number or similar to my protocol to try and detect it I
I found that this problem happens much less rarely (less than once a day) on a
UP machine than on an SMP one.
Given that I am wondering if it is some sort of locking issue, and if anyone
has seen anything similar?
I can supply the driver code if anyone is interested :)
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
-- Andrew Tanenbaum
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