Init_DA_Brds doesn't reinitialize NI6534

[JPF]

fter assigning all four 6534 ports to group 1 and output a sequence of data, I cannot reinitialize the board by calling Init_DA_Brds(). The function returns the correct board ID (216),
but the four ports remain in the output state.

According to version 7.1 of the Function Reference Help,

[This function} initializes the hardware and
software states of a National Instruments DAQ
device to ts [sic] default state ...

and

This function is useful for reinitializing the
device hardware and Traditional NI-DAQ software

Function Reference Help 7.1 gives the default state of the 6534 as DIO-24/DIO-32F/653X Devices/DIO-96 Default Conditions Digital Input and Output defaults:
Direction = Inp
ut.
Handshaking = Disabled.
Group assignments = No ports assigned
to any group.

Why doesn't Init_DA_Brds set the 6534 lines to the input direction?

[Sean_C.]

Hello JPF,

Thank you for contacting National Instruments.

How exactly are you checking the line directions after you call Init_DA_Brds function? Do you have another PCI-6534 you can test this with?
You might want to try upgrading to NI-DAQ 7.3 to see if this solves the problem.

Please respond with your results.

Sean C.
Applications Engineer
National Instruments

[JPF]

I first noticed that the outputs were still being driven because they were forward-biasing the Schotty bus-termination diodes in my external hardware. I verified that the outputs were still being driven by connecting an LED to an output pin and observing that it remained lit after I called the Init_DA_Brds function.

Why didn't NI attempt to verify my observation rather than challenge my assertion with a "How exactly are you checking the line directions" response? Suggesting that I try another PCI-6534 or that I "might want to try upgrading to NI-DAQ 7.3" rather ducks the question, wouldn't you say?

[JPF]

I should add that I noticed that the bus-termination diodes were forward biased whenever I powered down the external hardware. They were not forward-biased when the hardware was powered up.

[sergesl]

Hello JPF

I appologize for the way the question was asked. You are very knowledgeable of what you are dealing with, which is not always the case on the discussion forum. So it is always a good thing to make sure that we are answering the correct question. I checked the functions that you were refering to and effectively, it says that the lines should be reset to their default states which is indicated as input. In the manual for the 6534, I did not see the default state, but they mention the power up state. I will get a board in my computer and attempt the same thing and let you know what I find.
Sorry again if the reply appeared the way it did, but we did not mean to duck the question.

Serges Lemo
AE
National Instruments

[sergesl]

Hello JPF,

Sorry for the delay. It took me some time to get a PCI-6534 at my desk. I would like to have the code that you are using so I can attempt to reproduce it using exactely the same code.
In addition, I would like to know if you had your DPULL line connected to +5 V.

Serges L.