How Do I Use the VI Digital Group Config.vi with the 8255 chip (lab*, PC-DIO*, etc.)?Primary Software: Driver Software>>NI-DAQPrimary Software Version: 7.2 Primary Software Fixed Version: N/A Secondary Software: N/A Hardware: Legacy DAQ Devices>>Digital I/O>>PC-DIO-96, Legacy DAQ Devices>>Digital I/O>>PC-DIO-24, Legacy DAQ Devices>>Digital I/O>>PC-DIO-96PnP
Problem: How does Digital Group Config.vi work with the 8255 based devices like the PC-DIO series? Solution: This function will always try to set up your card for handshaking. So, for instance, if you have a PC-DIO-96 (which has 12 ports; 4 of these chips, 3 ports per chip), your card has port values that are from 0 to 11. Ports 2, 5, 8, and 11 are the ones that will be used for handshaking if possible. Now, in the function Group Config, you pass in an input called Port List. If this input includes any of the handshaking ports (2,5,8,11), then NONE of your ports will be set up for handshaking. So... If you were wanting to use ports 0 & 1, 3 & 4 for handshaking, but you included port 8 in the list (because you don't need handshaking for 6 & 7), then Group Config won't set up any for handshaking. Another problem might be that you call Group Config with ports 0 & 1, and then call port config with port 2. This will cause an error, since Group Config thinks that you want to use port 2 for handshaking. Trying to configure port 2 normally will trigger the error. So what are the solutions to these problems? Call Group Config various times or port config various times. Related Links: Attachments:
Report Date: 11/24/1997 Last Updated: 06/23/2004 Document ID: 13NERQHL |
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