Trigger Setup
For example, if the number of bytes is one, the oscilloscope will attempt to match the
fi
rst byte, second byte, third, and so
on within the packet.
If the number of bytes is two, the oscilloscope will try to match any two consecutive bytes, such as one and two, two and three,
three and four, and so on. If the oscilloscope
fi
nds a match, it will trigger.
Speci
fi
c byte matching (non-rolling window matching for a speci
fi
c position in the packet) for I
2
C, SPI, and
CAN.
You can trigger on a speci
fi
c byte for I
2
C, SPI and CAN in several ways:
For I
2
C and SPI, enter the number of bytes to match the number of bytes in the signal. Then use don’t cares (X) to mask the
bytes that you are not interested in.
For I
2
C, push the lower-bezel
Trigger On
to trigger on
Address/Data
. Push
Address
. On the side-bezel menu, push
Address
,
and rotate multipurpose knobs
a
and
b
as needed. Set the address to don’t cares (X) if you want to mask the address. The
data will be matched starting at the
fi
rst byte without using a rolling window.
For CAN, triggering occurs when the user-selected data input matches the data and quali
fi
er in the signal starting at the
fi
rst
byte. Set the number of bytes to match the number of bytes of interest. Use the data quali
fi
er to perform: =, !=, <, >, >=,
and <= operations. Triggering on identi
fi
er and data always matches the identi
fi
er and data selected by the user, with the
data starting at the
fi
rst byte. No rolling window is used.
RS-232 Bus Trigger Data Matching
You can trigger on a speci
fi
c data value for RS-232 bytes. If you de
fi
ned an end-of-packet character to use for RS-232 bus
decoding, you can use the same end-of-packet character as a data value for trigger data matching. To do so, choose the Tx End of
Packet or the Rx End of Packet character as the Trigger On selection.
DPO3000 Series Oscilloscopes User Manual
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