UNI-T UPO2102 User Manual page 91

User's Manual
14.1 RS232 Decoding
RS232 interface is an asynchronous transmission standard interface developed by the Electronics Industry
Association. It is usually available in DB-9 or DB-25 applications. It is suitable for communication with data
transmission rate in the range of 0～29491200/s and is widely used in microcomputer communication
interface. The data to be sent is combined into a specific set of serial bits according to the protocol rules and
sent in an asynchronous serial.
The data sent each time is according to the following rules: send one start bit firstly, then 5 to 8 is data bits,
the next is optional parity bits, and the last is one or two stop bits. The number of data bits is agreed upon
by the two communicating parties and can be 5 to 8 bits, no parity bits, or select odd or even parity. Stop bit
can select one or two bits. In the following description, one data string transmission is referred to as one
frame, as shown in Figure 14-1.
(1) Bus Decoding
Bus decoding menu can set bus status, display format and event list and position.
a. Bus status: set whether bus decoding is enabled.
b. Display format: set the display format of bus decoding, it can be hexadecimal, decimal, binary
system or ASCII (Only for RS232).
c. Event list: display data after decoding in data line, the corresponding line number, time, data and
parity data in list format for observing the long decoded data.
d. Vertical position: adjusting Multipurpose knob to change the bus position, which can set the range
to 10～190.
(2) Information Source
Set the trigger source, which can be CH1, CH2, CH3, CH4 or D0-D15. The current selected source will
display on the right corner of the screen. The source supports display and select digital channel only
when the digital channel is opened in LA.
Note: Only the channel that has been connected to the signal, select it as the trigger source that can
get the stable trigger and correct decoding.
 Instruments.uni-trend.com
Figure 14-1
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