UPO2000E decodes the input signals of the analog channels using common protocols, including parallel, RS232, I2C,
SPI. Users can easily find errors, debug hardware, and speed up development progress by protocol decoding, which
provides guarantees for completing projects with high speed and high quality.
6.1 RS232 Decoding
RS232 interface is the standard asynchronous transmission interface established by Electronic Industries Association.
Normally, there are two application types: DB-9 and DB-25, it is suitable for data transmission rate between 0 to 20000b/s,
which are widely used in PC communication interface. According to the protocol, the data will be combined to form a group
of specific serial bits, and sent out using asynchronous serial method. The data sent each time is composed according to
the following rules: a start bit is sent first, followed by 5~8 data bits, then an optional parity bit, and finally 1 or 2 stop bits.
The data bits size should be decided by the two communication parties, which can be chosen between 5 to 8 data bits;
there may be no parity bits, or the odd parity or even parity can be selected; and the stop bit can be 1 bit or 2 bits. In the
following instruction, a data string transmission is called one frame, shown in the figure below:
Chapter 6 Protocol Decoding
Rs232 Selection:
Press DECODE type , and select RS232 by the Multipurpose knob. You can also switch the trigger type by
consecutively pressing the type key, then press the Multipurpose knob to confirm.
Source:
Press the source button to select any of CH1, CH2, CH3, or CH4. The currently selected source is displayed at the upper
right corner of the screen.
Note: Only selecting the channel with connected signals as a trigger source can obtain a stable trigger and correct decoding.
Polarity:
Press the polarity button to choose the trigger polarity: positive polarity or negative polarity.
(1) Negative polarity: Opposite logic level polarity, i.e. high level is 0, low level is 1.
(2) Positive polarity: Normal logic level polarity, i.e. high level is 1, low level is 0.
Bit Width:
Specifies the data bit width of the RS232 protocol signal that needs to be decoded.
Press bit width to select 5bits, 6bits, 7bits, or 8bits.
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