Agilent Technologies DSO-X 4022A, User Manual

Page: 439 / 488

I2S Triggering and Serial Decode
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Agilent InfiniiVision 4000 X-Series Oscilloscopes User's Guide 439
3
Press the
Trigger Setup
softkey to open the I
2
S Trigger Setup Menu.
4 Press the Audio softkey; then, turn the Entry knob to choose to trigger
on
Left
channel events,
Right
channel events, or events that occur on
Either channel.
5 Press the Trigger softkey and choose a qualifier:
• Equal — triggers on the specified audio channel's data word when it
equals the specified word.
•
Not equal
— triggers on any word other than the specified word.
•
Less than
— triggers when the channel's data word is less than the
specified value.
• Greater than — triggers when the channel's data word is greater than
the specified value.
•
In Range
— enter upper and lower values to specify the range in
which to trigger.
• Out of Range — enter upper and lower values to specify range in which
trigger will not occur.
•
Increasing value
— triggers when the data value is increasing over time
and the specified value is met or exceeded. Set Trigger >= to the data
value that must be reached. Set Armed <= to the value to which the
data must fall before the trigger circuit is re- armed (ready to trigger
again). These settings are made in the current menu when
Base is
Decimal or in the Bits submenu when the Base is Binary . The Armed
control reduces triggers due to noise.
This trigger condition is best understood when the digital data
transferred over the I2S bus is considered in terms of representing
an analog waveform. The figure below shows a plot of sample data
transmitted over an I2S bus for one channel. In this example, the
oscilloscope will trigger at the 2 points shown since there are two
instances in which the data increases from a value below (or at) the
"Armed" value to a value greater than (or equal to) the specified
"Trigger" value.