User’s Manual MSO/UPO2000 Seri es
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7.14 RS232 Trigger
RS232 decoding trigger can set trigger condition, data, trigger coupling, trigger mode and decoding setting.
(1)
Trigger Condition
a. Start frame: Waveform triggering at the start bit of RS232 protocol. When send a single string or send
the same string several times, this trigger can be used to see a stable signal waveform, and if the sent
data changes, the corresponding waveform will also be change.
b. Error frame: When receiving 0 in the stop state or data error occurs in the middle of data bits.
c. Parity error: RS232 protocol sets the parity bit to 0 or 1 according to the parity rule when there is a
parity bit setting.
The parity rule is as follows.
Odd parity: If in data bits and parity bits, number of bit 1 is odd, then the transmission is correct.
Even Check: If in data bits and parity bits, number of bit 1 is even, then the transmission is correct.
Using this option, user can check the RS232 communication process and quickly find the transmission
process of parity error, so that you can easily locate the fault analysis.
d. Data: The trigger is generated when the data acquired by the oscilloscope is the same as the 2 bits
hexadecimal number set by the user. Using this option, user can quickly find the transmission signal of
the specific data that interested.
(2)
Data
It will be valid when the trigger condition is "Data", the range can set to 00 ~ FF (hexadecimal number).
(3)
Decoding Setting
Quickly enter the entrance of RS232 protocol decoding, refer to reference protocol decoding
7.15 I
2
C Trigger
I2C decoding trigger can set trigger coupling, trigger mode, operating direction, decoding setting and trigger
condition.
(1)
Operating Direction
It can set “write or read”.
a.
Write: It will be generated when the “read/write” bit of the I
2
C protocol is “write”.
b.
Read: It will be generated when the “read/write” bit of the I
2
C protocol is “read”.
(2)
Trigger Condition
It can set the I
2
C trigger condition to start, restart, stop, loss confirmed, address, data and address data.
a.
Start: It will be generated at the start time, that is, when the SCL is in high level, the SDA signal has
a falling edge.
