AI not workin on PCI-6221

[Matt31415]

I'm trying to get the analog input working for a 6221.  The board is on a Windows CE machine, so I can't use the DDk drivers.  Instead, I have written my own driver that allows me to read/write the registers directly.  I tested the digital I/O, and had no problems getting it to work, so I moved on to analog input.

For analog input, I used the method in aiex1.cpp, but I had to write my own code, because of the way my driver works(it's a stream driver, so I'm using lots of seeks and read/writes).  I believe I ported aiex1 without any obvious mistakes (although who knows...), however, when I run the program, all I get from the data FIFO is 0x0007FFFF (the maximum value).  

My input is a function generator creating a square wave from +7V to -7V at a bit less than 1Hz (so I don't think I'm having sampling issues).  The signal is input on pin 68, with the ground on pin 67.

I've looked at the status registers (joint_status 1 & 2 and ai_status_1) a bit, but I'm not really sure what I should be looking for. 

Does anyone have any general ideas for debugging this?   Any tricks I should be aware of?  

I tried changingAI_Output_Control.AI_CONVERT_Output_Select to kAI_CONVERT_Output_SelectActive_High (3) as discussed here:

http://forums.ni.com/ni/board/message?board.id=90&message.id=1041&query.id=1471127#M1041

but it didn't have any effect. 

[Matt31415]

I should also add that I tested the board setup (by booting my hardware under XP and using the NI tools) to confirm that I really was getting the analog signal that I thought I was, so it's probably not a hardware/connection issue.

[JoeFriedchicken]

Sorry for the delay, but has your driver's status or behavior changed? What have you tried and what did you expect to see but didn't?

[Matt31415]

I actually managed to get it working, although I'm not sure what the bug was.  Basically, I refactored my code, and somehow in the process of that, the AI started working.  My guess is that I was writing to the wrong register, or something like that.  Anyway, I now have a functioning driver.