We've got a device that uses a Cypress EZ-USB FX1 configured for CDC USB-Serial interface with the latest Cypress drivers. We're using NI-MAX with Switch Executive to interface with the serial device. I've setup the driver session to use a custom dll that uses the following settings:
VI_READ_BUF | VI_WRITE_BUF = 4096 bytes
VI_ATTR_WR_BUF_OPER_MODE = flush on access, same for RD mode
NI Spy shows that viOpen, setTimeout, set buffer sizes seem to work. Then we call a particular function implemented by the flashed FX1: setRelay(...), which elicits an I/O error having status 0xBFFF003E. (also, the relay gets set properly, I can hear the physical device switching, and the function returns nothing for the host to read).
However, doing the same thing manually in the VISA test panel works without error. Also, this used to work in Win7 with the old Cypress Win7 driver.
I've tried a bunch of stuff and haven't found an answer yet. Could someone here point me in the right direction?
Thanks