Serial I/O IRQ Method

Question

I am trying to do some simple I/O using an NI 9870 serial module in a cRIO with a NI-9014 host (LabVIEW 9, RIO 3.2.1) .  I am already using 3 DMA FIFO's for other things and was trying to pass the data in and out of the FPGA using an interrupt driven approach.  The baud rate is 57600 which if you do the calculations is ~60 characters in 15 milliseconds.  So here is what I tried and the RT Host immediately stops running after the timeout -  I realize there are all sorts of unhandled conditions in this code but it won't even eat one character....
So here is the FPGA side - there is a pre-allocated array of 255 elements - the loop runs until the array is nearly full or a timeout occurs - at which point an interrupt is generated -
Here is the host side - wait for an IRQ and then read the array, after that ack the IRQ -
Am I missing something simple ?????

Answer 1

Hello, is your wait function on the FPGA set to mSec or uSec or ticks? If its set to mSec then you will have your FPGA code wait 15 ms before even executing the second frame of the sequence so you will reach a timeout on the wait on IRQ every time (when set to 5 ms).
Also, I suggest having a stop control wired to the Stop Terminal of your host loop rather than a true constant so that you can manually stop the loop and have the code complete  ( including closing the FPGA VI reference which I assume is sitting right outside your while loop. This Close FPGA Reference stops your FPGA code and cleans up the reference.
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