514 Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide
33 UART/RS232 Triggering and Serial Decode
 
• Rx 1:Data — For use when the device under test data words are 9 bits in 
length including the alert bit (the 9th bit). Triggers only when the 9th (alert) 
bit is 1. The specified data byte applies to the least significant 8 bits 
(excludes the 9th (alert) bit).
• Rx 0:Data — For use when the device under test data words are 9 bits in 
length including the alert bit (the 9th bit). Triggers only when the 9th (alert) 
bit is 0. The specified data byte applies to the least significant 8 bits 
(excludes the 9th (alert) bit).
• Rx X:Data — For use when the device under test data words are 9 bits in 
length including the alert bit (the 9th bit). Triggers on a data byte that you 
specify regardless of the value of the 9th (alert) bit. The specified data byte 
applies to the least significant 8 bits (excludes the 9th (alert) bit).
• Similar choices are available for Tx.
• Rx or Tx Parity Error — Triggers on a parity error based on the parity you have 
set in the Bus Configuration Menu.
6 If you choose a trigger condition that includes "Data" in its description (for 
example: Rx Data), then press the Data is softkey, and choose an equality 
qualifier. You can choose equal to, not equal to, less than, or greater than a 
specific data value.
7 Use the Data softkey to choose the data value for your trigger comparison. This 
works in conjunction with the Data is softkey.
8 Optional: The Burst softkey lets you trigger on the Nth frame (1-4096) after an 
idle time you select. All trigger conditions must be met for the trigger to occur.
9 If Burst is selected, an idle time (1 µs to 10 s) can be specified so that the 
oscilloscope will look for a trigger condition only after the idle time has past. 
Press the Idle softkey and rotate the Entry knob to set an idle time.
If the setup does not produce a stable trigger, the UART/RS232 signals may be slow enough 
that the oscilloscope is AutoTriggering. Press the [Mode/Coupling] key, then press the Mode 
softkey to set the trigger mode from Auto to Normal.
To display UART/RS232 serial decode, see “UART/RS232 Serial Decode" on page 515.