88
3000 X-Series Oscilloscopes Advanced Training Guide
4
Serial Bus Decoding & Triggering, Search & Navigation, and Segmented Acquisition Labs
Your scope should now be triggering on Tx = 4D
HEX
while displaying this
byte at center- screen similar to
. Let’s now set up the scope to
capture a longer record of time (2 seconds) and review our data in a
“lister” format.
25
Set the scope’s timebase to
200.0 ms/div
.
26
Press
[Run/Stop]
to stop repetitive acquisitions.
27
Press the
[Serial]
front panel key.
28
Press the
Lister
softkey; then select
Serial 1 (UART/RS232)
using the Entry
knob.
29
Press the
Scroll Lister
softkey; then turn the Entry knob to scroll through
the decoded data.
As you scroll through the data, note that waveforms “track”. This means
that the frame that the arrow points to in the lister table corresponds to
the waveforms that are positioned at center- screen. If you want to zoom
in on a particular RS232/UART byte of data, either push the Entry knob,
or press the
Zoom to Selection
softkey. This particular stream of
RS232/UART data includes some infrequent parity errors (marked in red).
But locating the occasional parity bit error conditions can be difficult
using the manual scrolling method if the parity bit errors are very
infrequent. So let’s now perform an automatic search to find every
occurrence of parity bit errors on both the Tx and Rx data lines. We will
then automatically navigate to each of these occurrences.
Figure 62 Triggering on Tx = 4D
HEX
.