UNI-T UPO2102 User Manual page 92

User's Manual
(3) Polarity
Press Polarity key to select the trigger polarity to positive or negative.
a. Negative: opposite logic level polarity, i.e. high level is 0 and low level is 1.
b. Positive polarity: normal logic level polarity, i.e. high level is 1, low level is 0.
(4) Parity
Set the parity mode of data transmission. It can select no parity, even parity or odd parity.
(5) Bit Width
Specify the data bit width of RS232 protocol signal to be decoded. 5 bits, 6 its, 7 bits, 8 bits can be
selected.
(6) Bit Order
Specify whether the data bits of the RS232 protocol signal to be decoded is high bit at the front (MSB) or
low bit at the front (LSB). MSB or LSB can be selected.
a. MSB：The high bit of data is transmitted first.
b. LSB：The low bit of data is transmitted first.
(7) Stop Bit
Stop bit which is set stop bit for each data frame. It can set to 1 bit or 2 bits.
(8) Baud Rate
When RS232 is asynchronous transmission communication, there is no accompanying clock signal
during data transmission. In order to solve the determination of data bits, the protocol stipulates that
both parties of communication should agree on the bit rate. Usually, the bit rate is defined as the number
of bits that can be transmitted in 1s. For example, 9600 bps means 9600 bits can be transmitted in 1s. It
should note that the start, data, parity and stop bits are all counted as bit, so the baud rate does not
directly equal to the effective data transmitting rate. The oscilloscope will sample the bit values
according to the setting baud rate.
Baud rate can be 2400 bps, 4800 bps, 9600 bps, 19200 bps, 38400 bps, 57600 bps, 115200 bps or user-
defined. The baud rate can be adjusted via the Multipurpose knob or jog dial when user-defined is
selected.
It is recommended to set the baud rate based on the hardware and software of RS232 communication
protocol. Due to the basic model of this transmission protocol, RS232 protocol is usually used for short
distance (under 20m) and low speed (under 1 Mbps) transmission. Communication beyond this range is
susceptible interference and unreliable.
14.2 I C Decoding
2
I C trigger usually used to connecting micro-controller and peripheral equipment, it's widely applied in micro-
2
electronics area. This bus protocol has two lines to transmit, one line is serial data SDA,and another line is
serial clock SCL. Communicated by master-slave system which can both-way communication between
 Instruments.uni-trend.com
MSO/UPO2000 Seri es
92 / 137