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Operation Theory
Acquisition_in_progress
Scan_start
ADCONV
(M_counter = M = 3, PSC_counter=0)
Acquired data
Acquired & stored data
(M scans)
Trigger signals which occur in the shadow
region(the first M scans) will be ignored
Operation start
Trigger
The first M scans
Figure 13: Pre-trigger with M_enable = 1
Note:
The PSC_counter is set to 0 in pre-trigger acquisition mode.
Middle-Trigger Acquisition
Use middle-trigger acquisition in applications where you want to collect
data before and after a trigger event. The number of scans (M) stored
before the trigger is specified in M_counter, while the number of scans (N)
after the trigger is specified in PSC_counter.
Like pre-trigger mode, the number of stored data could be less than the
specified amount of data (M+N), if an external trigger occurs before M
scans of data are converted. The
M_enable
bit in middle-trigger mode
takes the same effect as in pre-trigger mode. If
M_enable
is set to 1, the
trigger signal will be ignored until the first M scans of data are converted,
and it assures the user with (M+N) scans of data under middle-trigger
mode. However, if
M_enable
is set to 0, the trigger signal will be accepted
at any time. Fig 14 shows the acquisition tim ing with M_enable=1.
