Trigger Mode/Coupling 11
Agilent InfiniiVision 3000 X-Series Oscilloscopes User's Guide 179
 
Trigger Indicator The trigger indicator at the top right of the display shows whether triggers 
are occurring.
In the Auto trigger mode, the trigger indicator can show:
• Auto? (flashing) — the trigger condition is not found (after the 
pre- trigger buffer has filled), and forced triggers and acquisitions are 
occurring.
• Auto (not flashing) — the trigger condition is found (or the pre- trigger 
buffer is being filled).
In the Normal trigger mode, the trigger indicator can show:
• Trig'd? (flashing) — the trigger condition is not found (after the 
pre- trigger buffer has filled), and no acquisitions are occurring.
• Trig'd (not flashing) — trigger condition is found (or pre- trigger buffer is 
being filled).
When the oscilloscope is not running, the trigger indicator area shows 
Stop.
When to Use Auto
Trigger Mode
The  Auto trigger mode is appropriate when:
• Checking DC signals or signals with unknown levels or activity.
• When trigger conditions occur often enough that forced triggers are 
unnecessary.
When to Use
Normal Trigger
Mode
The  Normal trigger mode is appropriate when:
• You only want to acquire specific events specified by the trigger 
settings.
• Triggering on an infrequent signal from a serial bus (for example, I2C, 
SPI, CAN, LIN, etc.) or another signal that arrives in bursts. The Normal 
trigger mode lets you stabilize the display by preventing the oscilloscope 
from auto- triggering.
• Making single- shot acquisitions with the [Single] key.
Often with single- shot acquisitions, you must initiate some action in the 
device under test, and you don't want the oscilloscope to auto- trigger 
before that happens. Before initiating the action in the circuit, wait for 
the trigger condition indicator Trig'd? to flash (this tells you the 
pre- trigger buffer is filled).
See Also • "Forcing a Trigger" on page 143
• "To set the trigger holdoff" on page 182