One of our custom VXI board developers has a board that holds TTL Trigger line 6 low on certain startup conditions. Once intialized, the board releases 6 to the floating high state. I coded the following snippet (with appropriate InitVXILibrary, etc.) to try to use the ON/OFF protocol. My intent to detect when the board is happy (6 is released) from NI-VXI library code on our Linux host with PCI-MXI-2 card in place.
rc = EnableTrigSense(-1, 6, 1); // 1 == OFF
I get a run-time failure code of -3, which thedocumentation says is invalid line or protocol. I get the same for protocol 0 (ON). But if I specify protocols 2, 3, 4, 5, or 6 (START, STOP, SYNC, SEMI-SYNC, and ASYNC repsectively), then the Enable succeeds, but of co
urse is not what I want.
Have I misunderstood the ON/OFF protocol to be what I want to use? Why is it being rejected by the Enable call?