Keysight 4000 X-Series, Руководство по продвинутой подготовке

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88 4000 X-Series Oscilloscopes Advanced Training Guide
4
Serial Bus Decoding & Triggering, Search & Navigation, and Segmented Acquisition Labs
You should now see four digital waveforms captured by the scope’s digital
channels of acquisition similar to Figure 55 . These SPI training signals are being
generated by the scope’s built-in pattern generator and routed directly to the
scope’s digital acquisition system; bypassing the logic probe. Note that in a real
measurement application such as this, you would use the scope’s analog input
channels and/or logic probe to capture these signals from your system.
D9 is the MOSI data signal (Master-out, Slave-in), and D8 is the MISO data signal
(Master-in, Slave-out). You can also think of these signals as serial data-out and
serial data-in relative to the Master. D7 is the SPI clock signal (CLK), and D6 is the
chip select low-enable signal (~CS). This signal is sometimes referred to as
Slave-select (SS). Note that the “~” symbol simply means “not” or “low-enable”.
Let’s now set up the scope to decode these SPI signals.
12
Press the
[Serial]
front panel key.
13
Tap the Mode I
2
C softkey; then double-tap SPI to enable.
14
Tap the Signals softkey.
15
Tap the Clock softkey twice to open the menu; then double-tap D7 to set it as as
the clock source.
16
Press the (Back) front panel button to return to the previous menu.
Figure 55 Capturing 4-wire SPI signals using the scope’s digital channels of acquisition
(MSO).
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