AnsweredAssumed Answered

Using Port C for Material I/O Handler

Question asked by stewp on Feb 28, 2007
Latest reply on Mar 9, 2007 by stewp
I want to throw a TTL switch after triggering a sweep on my PNA, and then issue another sweep to collect full-polarization RCS data in an anechoic chamber.  I had hoped to use Port C on the Material I/O handler so that I could easily get to this signal on the Port C pass-thru to the Auxiliary IO port.  When I initialize the PNA and acquire all of my interfaces, I get an interface to the IHWMaterialHandlerIO pointer.  I then use this code to set port C to output:

    // Get the Material Handler IO

    // Set Port C to Output and Port D to Input

This seems to work, as I probe pin #30 of the Material I/O connector I see a TTL low, which equals Port c as Input mode.  So far so good.

Now, when I look at pins #5 (GND) and #22 (C0), I always see about 5V.  I then use this code:

  tagVARIANT t;
  _variant_t tv;

  t.iVal  =0;
  tv.iVal =t.iVal;

  if (pIOHandler==NULL)


  if (SUCCEEDED(hr))

to try to send a TTL low to Pin #22 of the Auxiliary I/O connector, and I never see it change from the 5V value.  I is apparently not this simple?  What am I doing incorrectly to be able to toggle pin #22 (C0) of the Auxialiary I/O connector?  The Help file seems to say that the port is latched, but I must be missing something.  Any help or examples will be greatly appreciated.  Thanks in advance.