3.6.1.8 External Trigger Control
The operation steps of
post-trigger
are given as follows:
Step 1: Disable all external trigger
External trigger signal
Step 2: Set the pacer rate of timer-1
Step 3: Clear FIFO & disable timer-1
CHn
Step4: Wait until external trigger signal
to enable timer-1
t
Step 5: Fetch N data(N=End-Start)
Start
End
External post-trigger timing
Step 6: Stop all timer
The operation steps of
pre-trigger
are given as follows:
Step 1: Disable all external trigger
External trigger signal
Step 2: Set the pacer rate of timer-1
Step 3: Clear FIFO & enable timer-1
CHn
Step 4: Circular-fetch N-data until
external trigger signal to disable
timer-1 (N=End-Start)
Start
End
External pre-trigger timing diagram
t
Step 5: Stop all timer
NOTE: The circular-fetch operation is performed by software
The operation steps of
middle-trigger
are given as follows:
Step 1: Disable all external trigger
External trigger signal
t
Start
End
N2
Step 2: Set the pacer rate of timer-1
CHn
Step 3: Clear FIFO & enable timer-1
Step4: Circular-fetch N-data until
external trigger signal (N=End-
Start)
External middle-trigger timing diagram
Step 5:Fetch more N2-data & stop timer-1
Step 6: Stop all timer
NOTE: The circular-fetch operation is performed by software
z
Note 1: The external trigger operation must use with the MagicScan controller.
The software flowchart of external trigger is given in next page.
z
Note 2: The post-trigger operation can use all MagicScan function.
z
Note 3: The user can
'
t enable MagicScan HI/LO alarm and digital filter function
in the pre-trigger & middle-trigger operation.
PCI-1202/1602/1800/1802 Hardware User’s Manual
(Ver. 4.2, Dec/2009, PMH-014-42)---- 49