3-41
Triggering the Oscilloscope
To use SPI triggering
5 Press the
Frame by
softkey to select a framing signal that the oscilloscope
will use for determining which clock edge is the first clock edge in the
serial stream.
You can set the oscilloscope to trigger during a high chip select (
CS
), a low chip
select (
~CS
), or after a
Timeout
period during which the clock signal has been
idle.
• If the framing signal is set co
CS
, the first clock edge as defined (rising or
falling) seen after the
CS
signal transitions from low to high is the first clock
in the serial stream.
• If the framing signal is set to
~CS
, the first clock edge as defined (rising or
falling) seen after the
~CS
signal transitions from high to low is the first clock
in the serial stream.
• If the framing signal is set to
Timeout
, the oscilloscope generates it’s own
internal framing signal after it sees inactivity on the serial clock line.
Timeout
Select
Timeout
in the
Frame by
softkey, then select the
Timeout
softkey
and turn the Entry knob to set the minimum time that the Clock signal must be
idle (not transitioning) before the oscilloscope will search for the Data pattern
on which to trigger. When you press the
Frame by
softkey, the graphic shown on
the previous page changes to show timeout selection or the current state of the
chip select signal.
The Timeout value can be set anywhere from 500 ns to 10 s.
Chip Select
Press the
CS
or
~CS
softkey or turn the Entry knob to select the
channel that is connected to the SPI frame line. The label (
~CS
or
CS
) for the
source channel is automatically set. The data pattern and the clock transition
must occur during the time when the framing signal is valid. The framing signal
must be valid for the entire data pattern.
As you press the
CS
or
~CS
softkey (or rotate the Entry knob on mixed-signal
oscilloscopes), the
CS
or
~CS
label for the source channel is automatically set
and the channel you select is shown in the upper-right corner of the display
next to "
SPI
". When you press the
Frame by
softkey, the graphic shown on the
previous page changes to show timeout selection or the current state of the chip
select signal.
Adjust the trigger level for the selected analog channel by turning the Trigger
Level knob. Select
Threshold
in the
D7 Thru D0
or
D15 Thru D8
menu to set the
level for digital channels. The value of the trigger level or digital threshold is
displayed in the upper-right corner of the display.
Summary of Contents for 54621A
Page 4: ...iv ...
Page 10: ...Contents 6 ...
Page 11: ...1 Getting Started ...
Page 38: ...1 28 ...
Page 39: ...2 Front Panel Overview ...
Page 63: ...3 Triggering the Oscilloscope ...
Page 117: ...4 MegaZoom Concepts and Oscilloscope Operation ...
Page 171: ...5 Making Measurements ...
Page 222: ...5 52 Making Measurements Making overshoot and preshoot measurements ...
Page 223: ...6 Utilities ...
Page 239: ...7 Performance Characteristics ...
Page 250: ...7 12 Performance Characteristics Agilent 54620 series Performance Characteristics ...
Page 260: ...7 22 ...