RIGOL
Chapter 3 Demo Board Applications
User’s Guide for DS6000 Demo Board
3-40
3.3.3 I2C Signal
1.
Protocol Explanation
The start condition: when SCL is high level and SDA switches from high level to low level.
The stop condition: when SCL is high level and SDA switches from low level to high level.
The 8bits following the start condition is the slave device address and the read/write bit. The
address bit can also be 10bits and at this point, it occupies two bytes.
When the read/write bit is 0, the oscilloscope sends data (write); and when it is 1, the
oscilloscope reads data (read).
Every time a byte is sent by the host device, the slave device is asked to send a answer signal
and at this point, the host device restores to the high level; if the signal is successfully received
by the slave device, the level of the answer bit drops and if the signal is not successfully received,
the answer bit holds in high level.
2.
Signal Explanation
Signal Output Pin:
I2C_SCL, I2C_SDA
I2C signal with 125 kHz rate. The content is “RIGOL”. The data frame head and the read/write
bit would change.
3.
Functions
I2C trigger, I2C decoding
4.
Demonstration and Result
Connect I2C_SCL and GND to CH1 properly using the probe; connect I2C_SDA and GND to CH2
properly using the probe.
Set the trigger type to “I2C”, SCL to “CH1”, SDA to “CH2”, the trigger condition to “Data”, the
data to “LHLH LLHL” (namely the decimal number 82 and the ASCII code of the character “R”)
and the trigger mode to “Auto”; adjust the vertical position and trigger level to appropriate
values to make the oscilloscope trigger stably.
When the oscilloscope is in T’D state, set the decoding type to “I2C”, the ary to “ASCII”, the SCLK
threshold to “1.00V” and the SDA threshold to “1.00V”. Set the BUS status to “ON” and the
demonstration result is as shown in the figure on the next page.
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