I2C/SPI Triggering and Serial Decode 28
Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide 449
Clock Timeout — Select Clock 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.
The Timeout value can be set anywhere from 100 ns to 10 s.
When you press the Frame by softkey, the Display Info graphic changes to
show timeout selection or the current state of the chip select signal.
b Press the Threshold softkey; then, turn the Entry knob to select the chip select
signal threshold voltage level.
The threshold voltage level is used in decoding, and it will become the
trigger level when the trigger type is set to the selected serial decode slot.
When Display Info is enabled, information about the selected signal sources and
their threshold voltage levels, as well as a waveform diagram, appears on the
screen.
SPI Triggering
To set up the oscilloscope to capture SPI signals, see “Setup for SPI Signals" on
page 445.
After the oscilloscope has been set up to capture SPI signals, you can then trigger
on a data pattern that occurs at the start of a frame. The serial data string can be
specified to be from 4 to 32 bits long.
When you select the SPI trigger type and Display Info is enabled, a graphic is
displayed showing the current state of the frame signal, clock slope, number of
data bits, and data bit values.
1 Press [Trigger].
2 In the Trigger Menu, press the Trigger Type softkey; then, turn the Entry knob to
select the serial slot (Serial 1 or Serial 2) on which the SPI signals are being
decoded.
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