Agilent Technologies InfiniiVision 3000 X- Series, Руководство по продвинутой подготовке, Страница: 100 / 128

100 3000 X-Series Oscilloscopes Advanced Training Guide
4
Serial Bus Decoding & Triggering, Search & Navigation, and Segmented Acquisition Labs
You should now see on your scope’s display what appears to be an
un- triggered display of a digital burst signal similar to
Figure 73 . Your
scope is actually triggering on random rising edges of channel- 1, which is
the scope’s default trigger condition. But this signal is too complex to
establish a unique trigger point using simple edge triggering. This signal is
a packet/frame of LIN serial bus traffic. Let’s first set up the scope to
intelligently decode this serial data stream based on the LIN protocol, and
then we will establish a more unique trigger point using LIN triggering.
9 Press the
[Serial]
front key.
10 Press the
Mode I
2
C
softkey; then select the
LIN
serial decode mode using
the Entry knob.
11
Press the Signals softkey and verify that the Baud Rate is set to 19.2 kb/s .
You should now see LIN protocol decoding of this signal on your scope’s
display similar to
Figure 74 , but we still haven’t established stable
triggering. The scope is still triggering on any rising edge of channel- 1
(default trigger condition). Let’s now set up the scope to trigger on a LIN
frame with the ID = 21
HEX
.
12 Press the
[Trigger]
front panel key.
13 Select
Serial 1 (LIN)
using the Entry knob.
14 Press
Trigger: Sync
; then select
ID – Frame ID
using the Entry knob.
15 Press the
Bits
softkey.
16 Press the
Frame ID
softkey; then set ID =
0x21
using the Entry knob.
Figure 74 Decoding a LIN bus while triggering on any rising edge of the input signal.