side effects when switching ports on PCI-DIO96 from output to input using daqmx API

[markus kossmann]

Hallo, 
please have a look on the attached test program source code. Why does changing the configuration of port0 and port1 affect port2 ?
Programming error, bug in DAQmx or hardware feature ?  


daqtest.c:
http://forums.ni.com/attachments/ni/70/5818/1/daqtest.c

[markus kossmann]

I saw that problem with a PCI-DIO96 (see comment at top of testprogram and message subject) .
Now I've switched to a 6509 and the problem doesn't show up any more.
 
So it's probably not a programming error, but either a error in the PCI-DIO96 driver
or a hardware feature  of the PCI-DIO96.
The 12 ports of the PCI-DIO96 a grouped in 4 groups with each 3 ports ( there are also 4 ICs M82C55 on the card).
So it might be sensible to assume that there a some depencies within a group  of ports. But I don't know if the driver should be able to work around such a  depency if it exists. 
 
The function panels in MAX  only allow access per port but not parallel access to several ports at the same time. So I can't decide if any changes seen with the FPs are caused by MAX ( when switching the port) or by the driver or the hardware itself.
 

[Matthieu Papaux]

<a href="http://digital.ni.com/public.nsf/websearch/3E25A9780F2C48B986256120005AF098?OpenDocument" target="_blank"></a> Hi Markus,I talked with an expert and he gave me this explanation:<a href="http://digital.ni.com/public.nsf/websearch/3E25A9780F2C48B986256120005AF098?OpenDocument" target="_blank">KB 0489FD8Q: Why Do All My Digital I/O Ports Reset When I Configure One Port?</a>
The PCI-DIO-96 device uses the 8255 digital chip, and every time
that a task containing any lines on the device are reset, all lines on
all ports will reset to their default state.&nbsp; I would post a link to
this knowledgebase on the discussion forum to give the customer some
background information, and then instruct him to only create and clear
his digital tasks once in his program.&nbsp; I hope than that give a response to your question.Matthieu PapauxNI Germany