User`s guide

Triggering 4
InfiniiVision Oscilloscopes User’s Guide 169
using the User Baud softkey. You can set the UART baud rate from 1.2 kb/s to
3.0000 Mb/s in increments of 100 b/s.
dPolarity: Select idle low or idle high to match your device under test’s state when
at idle. For RS232 select idle low.
e Bit Order: Select whether the most significant bit (MSB) or the least significant bit
(LSB) is presented after the start bit in the signal from your device under test. For
RS232 select LSB.
12 Press the up arrow softkey to return to the previous menu.
13 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.
14 Press the Trigger Setup softkey and set up the desired trigger condition:
• Rx Start Bit — The oscilloscope triggers when a start bit occurs on Rx.
• Rx Stop Bit — Triggers when a stop bit occurs on Rx. The trigger will occur on the
first stop bit. This is done automatically whether the device under test uses 1, 1.5,
or 2 stop bits. You do not need to specify the number of stop bits used by the device
Under test.
• Rx 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 (no 9th (alert) bit).
• 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.