User Manual

Table Of Contents
Acquire the Sign
al
Physical Layer Bus Activity
Oscilloscope waveform traces from analog channels 1 to 4, digital channels D15 to D0, M ath waveforms, and the traces you
see when you choose to display a bus always show the physical layer bus activity. In the physical layer display, bits that were
transmitted earlier are to the left, and bits that were transmitted later are to the right.
I
2
C, and CAN and CAN FD buses transmit the MSB (most signicant bit) rst
SPI buses do not specify a bit order
RS-232 and LIN buses transmit the LSB (least signicant bit) rst
NOTE. The oscilloscope displays the decode traces and event tables for all buses with the MSB on the left and LSB
on the right.
For example, an RS-232 signal (after the start bit) might be high, high, high, low, high, low, lo w, and high. Since the RS-232
protocol uses high for zero and low for one, this value would be 0001 0110.
Since the decode displays the MSB rst, the o scilloscope reverses the order of the bits and displays 0110 1000. If the bus
display is set to hex, the value displays as 68. If the bus display is set to AS CII, the value displays as h.
Event Table
In addit
ion to seeing decoded packet data on the bus waveform itself, you can view all captured packets in a tabular
view much like you would see in a software listing. Packets are time stamped and listed consecutively with columns for
each component (Address, Data, etc.). You can save the event table data in .CSV format for detailed ofine analysis.
Using t
he Event Table, you can:
Scroll
the event table to update the view point in the waveform.
Each ro
w in the event table represents a time-stamped byte, packet, or word, depending on the bus type. As you scroll
the event table using the multipurpose knob, the view point in the oscilloscope display updates to show the position in the
waveform corresponding to the event in the Event Table.
Save the event table. (See page 68, Setting Up Bus Parameters.)
Saving an event table may save more data than can be presented on the oscilloscope. Use these saved les for
in-de
pth ofine analysis.
80 MDO3000 Series Oscilloscopes User Manual