User Manual
93
UART/RS232 Triggering
To trigger on a UART (Universal Asynchronous Receiver/Transmitter) signal connect the
oscilloscope to the Rx and Tx lines and set up a trigger condition. RS232 (Recommended
Standard 232) is one example of a UART protocol.
1. Press
Setup
button on the front panel to enter the TRIGGER function menu.
2. Press the
Type
softkey; then, turn the
Universal Knob
to select the serial slot (
Serial
1
or
Serial 2
) on which the UART/RS232 signals are being decoded above.
3. Press the
Trigger
Setting softkey to enter the UART TRIG SET menu.
Figure 49 UART TRIG SET Menu
4. Press the
Source Type
softkey to select TXDATA or RX DATA.
5. Press the
Trigger
softkey and set up the desired trigger condition:
Start
— The oscilloscope triggers when a start bit occurs.
Stop
— Triggers when a stop bit occurs on Rx. vice under test uses 1, 1.5,
•
Data
— Triggers on a data byte that you specify. For use when the device under
test data words are from 5 to 8 bits in length
a.
Press the
Compare Type
softkey, and choose an equality qualifier. You can
choose equal to, less than, or greater than a specific data value.
b.
Use the
Value
softkey to choose the data value for your trigger comparison.
This works in conjunction with the
Compare Type
softkey. The range of the
Value is ox00 to oxff.
Figure 50 UART Trigger
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