372 Keysight InfiniiVision 3000 X-Series Oscilloscopes User's Guide25 I2C/SPI Triggering and Serial Decode3 Press the Serial softkey, turn the Entry knob to select the desired slot (Serial 1 orSerial 2), and press the softkey again to enable decode.4 Press the Mode softkey; then, select I2C trigger type.5 Press the Signals softkey to open the I2 C Signals Menu.6 For both the SCL (serial clock) and SDA (serial data) signals:a Connect an oscilloscope channel to the signal in the device under test.b Press the SCL or SDA softkey; then, turn the Entry knob to select the channelfor the signal.c Press the corresponding Threshold softkey; then, turn the Entry knob to selectthe signal threshold voltage level.The threshold voltage level is used in decoding, and it will become thetrigger level when the trigger type is set to the selected serial decode slot.Data must be stable during the whole high clock cycle or it will beinterpreted as a start or stop condition (data transitioning while the clock ishigh).The SCL and SDA labels for the source channels are automatically set.I2C TriggeringTo set up the oscilloscope to capture I2C signals, see "Setup for I2C Signals" onpage 371.After the oscilloscope has been set up to capture I2C signals, you can trigger on astop/start condition, a restart, a missing acknowledge, an EEPROM data read, oron a read/write frame with a specific device address and data value.1 Press [Trigger]; then, select the I2C trigger type.2 Press [Trigger].3 In the Trigger Menu, press the Trigger softkey; then, turn the Entry knob toselect the serial slot (Serial 1 or Serial 2) on which the I 2 C signals are beingdecoded.
