Hello DianeS,
Thank you for your reply. Let me explain what we would like to do:
We would like to sample two digital data lines, where a third line (a clock) serves as a digital trigger (edge, falling). The clock rate is ~1KHz. Data on the data lines is synchronized by the clock, and there are 10 samples in every cycle of 100msec. So actually we need to sample 10 bits of data (on each line), which are transmitted in a 10msec period in every 100msec cycle.
You can see everything in the attached files. File scope_1.jpg shows the general behavior: the upper (yellow) line is the clock, the lower lines are the data lines we want to sample. File scope_2.jpg shows a magnification of a 10msec period.
We need the trigger because we want to sample data ONLY in the 10msec where there is actual data, we don’t want to sample in the 90msec "silent" period. The samples must be written to an output file, and sampling is planned to take place for several days (may be even for a month or so), so we need to reduce the size of the output file to a minimum. Using the trigger will let us reduce the size of the output file to 10% of the size we would get had we not used a trigger.
