Agilent Technologies 54622A User Manual page 81

3 Connect an oscilloscope channel to the serial data (SDA) line in the
circuit under test, then set the
As you press the Data softkey (or rotate the Entry knob on mixed-signal
oscilloscopes), the channel you select is shown in the upper-right corner of the
2
display next to "I
C".
Adjust the trigger level for the selected analog channel by turning the Trigger
Level knob. For the mixed-signal oscilloscope, select Threshold in the D7 Thru
D0 or D15 Thru D8 menu to set the level for digital channels assigned to the clock
and data lines. The value of the trigger level or digital threshold is displayed in
the upper-right corner of the display.
Data needs to be stable during the whole high clock cycle or it will be interpreted
as a start or stop condition (data transitioning while the clock is high).
4 Press the softkey to select one of the following I
Trigger:
conditions:
Start Condition: the oscilloscope triggers when data (SDA) transitions from high
to low while the clock (SCL) is high. For triggering purposes (including frame
triggers), a restart is treated as a start condition.
Stop Condition: the oscilloscope triggers when data (SDA) transitions from low
to high while the clock (SCL) is high.
SD A
SCL
Start Address
Condition
Frame (Start: Addr: Read: Ack: Data) or
Frame (Start: Addr: Write: Ack: Data): the oscilloscope triggers on a read or write
frame on the 17th clock edge if all bits in the pattern match.
Frame (Start: ~[Addr: Read: Ack: Data]) or
Frame (Start: ~[Addr: Write: Ack: Data]): same as the read or write frame above,
except the oscilloscope triggers on the 17th clock edge if any bits in the pattern
do not match.
channel softkey to that channel.
Data
ACK DATA
R/W
Triggering the Oscilloscope
To use I2C triggering
2
C trigger
Stop
ACK
Trigger
Condition
point
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