User manual

Protocol Analysis
R&S
®
RTO
270User Manual 1316.0827.02 ─ 06
For SPI buses, the R&S RTO provides the following trigger possibilities:
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On frame start
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On a serial pattern
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On a serial pattern at a specified position
10.3.2 Analyzing SPI Signals
10.3.2.1 Configuring SPI Signals
For configuration, assign the lines to the input channels, and define the active states and
the logical thresholds.
For details on configuration settings, see chapter 10.3.3.1, "SPI Configura-
tion", on page 271.
1. Press the PROTOCOL key on the front panel.
2. At the left hand-side, select the vertical tab of the bus you want to set up.
3. Select the "Configuration" tab.
4. Tap the "Protocol" button and select the protocol: "SPI".
5. Optionally, you can enter a "Bus label" in the "Display" tab.
6. Tap the "SCLK Source" button, and select the waveform of the clock line.
7. Set the polarity (clock mode) for SCLK.
8. For each of the available SS, MISO and MOSI lines, assign the waveform and define
the polarity (active state) of the line.
9. Set the logical thresholds: Either according to technology definition with "Preset", or
to the middle reference levels with "Set to 50%", or enter a user-defined value directly
in the "Threshold" fileds.
10. Set the "Bit order", "Word length", and "Frame condition" according to your signal.
10.3.2.2 Triggering on SPI
Prerequesites: A bus is configured for the SPI signal to be analyzed.
1. Press the TRIGGER key.
2. Tap the "Source" button and select the "Serial" trigger source.
3. Select the serial bus that is set to SPI.
4. Select the "Trigger type".
5. For more complex trigger types, enter the data pattern conditions
SPI Bus