Agilent Technologies 54621A User Manual page 88

Triggering the Oscilloscope
To use I2C triggering
EEPROM Data Read: the trigger looks for EEPROM control byte value 1010xxx
on the SDA line, followed by a Read bit and an Ack bit. It then looks for the data
value and qualifier set by the Data softkey and the Data is softkey. When this
event occurs, the scope will trigger on the clock edge for the Ack bit after the
data byte. This data byte does not need to occur directly after the control byte.
SDA
SCL
Control byte
Start or
Restart Condition
Frame (Start: Addr7: Read: Ack: Data) or
Frame (Start: Addr7: Write: Ack: Data): the oscilloscope triggers on a read or write
frame in 7-bit addressing mode on the 17th clock edge if all bits in the pattern
match. For triggering purposes, a restart is treated as a start condition.
Read Write
SDA
SCL
Address
Start or
Restart
Condition
3-26
Read
Data
Ack
R/W
R/W Data
Ack
Trigger point
17th clock edge
Ack
Trigger point
Ack
Stop
Condition