User manual

RIGOL Chapter 8 Protocol Decoding
8-6 MSO2000A/DS2000A User’s Guide
Press Decode1  Decode to select “RS232” to open the RS232 decoding function
menu.
If the current trigger type of the trigger system is RS232, pressing CopyTrig can
copy the current RS232 trigger settings (include the source channel, polarity, stop bit,
even-odd check mode, data bits and baud rate) and apply them to the RS232
decoding function. Then, if needed, you can still set the RS232 decoding parameters
according to the introductions below.
Note: The copy function is only available when the current trigger type is “RS232”;
otherwise, CopyTrig is not available.
1. TX and RX Channel Setting
Press TX to select any channel (CH1, CH2 or any channel of D0-D15) as the
transmitting channel and when “None” is selected, no transmitting channel is set.
Use the same method the set the RX channel.
When an analog channel is selected for TX or RX, you need to set a threshold
by pressing the TX or RX menu. The range is from (-5*vertical scale - vertical
position) to (5*vertical scale - vertical position) and the default is 0 V.
2. Polarity Setting
Press Polarity to select “Normal” (negative logic, namely the high level is logic
“0” and the low level is logic “1”) or “Invert” (positive logic, namely the high level
is logic “1” and the low level is logic “0”) and the default is “Normal”.
3. Endian Setting
Press Endian to select “LSB” or “MSB” and the default is “LSB”.
4. Baud Rate Setting
Press Baud to select the desired baud rate and the default is 9600 bps. If “User”
is selected, press Setup and use or the inner knob of the navigation knob to
adjust the baud rate at a relatively smaller step or turn the outer knob of the
navigation knob to adjust the baud rate at a relatively larger step. The range is
from 110 bps to 20 Mbps.
5. Data Packet Setting
As mentioned before, in RS232, you need to set the start bit, data bits, check bit
(optional) and stop bit of each frame of data. “Start Bit” is specified by the