Hey guys,
I am writing a program to snoop on the SPI communication between a microcontroller and two MAX-7221 display drivers. Essentially, I want to read the Din pin of both chips and convert the data streams into the corresponding numbers that are being displayed on the devices front pannel (each chip controls two 3 digit numbers, 6 digits in all). The data is 16 bits and contains a 4 bit address and a 4 bit code B representation of the number. I recognize both of those values in the vi, convert the code B into decimal, and use the address to combine each digit into corresponding 3 digit numbers that I can display and save to a file.
Each chip has a Din line that contains the data, a clock, and a load signal (called CS). In my vi I aquire data using the external clock signal and use a pause trigger to aquire only when CS is low. This worked perfectly for collecting data from one MAX-7221 chip, but I started to run into problems when trying to aquire data from both chips simultaneously.
Since I am using two differnt clock and trigger signals, I couldn't use a single DAQ. I had a PCI-6251 laying around and decided to use that to aquire from one chip and my original USB-6361 to aquire from the other. Aquiring data from either chip with the USB-6361 works perfectly, but when I try to aquire from both DAQs simultaneously I get Error 200452 associated with the PCI-6251 pause trigger.
I have been doing a ton of digging, but I can't seem to figure out what the issue is. The NI website says that the PCI-6251 supports pause triggering, and no matter what channel I use I still get the same error. I even tried to use other types of triggers, but no matter what I do I get Error 200452.
Thoughts?
Thanks in advance!
Colin