448 Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide
28 I2C/SPI Triggering and Serial Decode
 
In the SPI Chip Select Menu:
a 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 to CS (or ~CS), the first clock edge as defined, 
rising or falling, seen after the CS (or ~CS) signal transitions from low to 
high (or high to low) is the first clock in the serial stream.
Chip Select — Press the CS or ~CS softkey; then, 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.
• 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.