UART/RS232 Triggering and Serial Decode 27
Agilent InfiniiVision 3000 X-Series Oscilloscopes User's Guide 409
 
UART/RS232 Triggering
To set up the oscilloscope to capture UART/RS- 232 signals, see "Setup for 
UART/RS232 Signals" on page 407.
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  [Trigger].
2 In the Trigger Menu, press the Trigger softkey; then, turn the Entry knob 
to select the serial slot (Serial 1 or Serial 2) on which the UART/RS232 
signals are being decoded.
3 Press the Trigger Setup softkey to open the UART/RS232 Trigger Setup 
Menu.
4 Press the Base softkey to select Hex or ASCII as the base displayed on 
the Data softkey in the UART/RS232 Trigger Setup Menu.
Note that the setting of this softkey does not affect the selected base of 
the decode display.
5 Press the Trigger softkey and set up the desired trigger condition:
• Rx Start Bit — The oscilloscope triggers when a start bit occurs on Rx.
In the serial decode display, the most significant bit is always displayed on the left 
regardless of how Bit Order is set.