I2C/SPI Triggering and Serial Decode 28
Keysight InfiniiVision 3000T X-Series Oscilloscopes User's Guide 443
Interpreting I2C Decode
• Angled waveforms show an active bus (inside a packet/frame).
• Mid-level blue lines show an idle bus.
• In the decoded hexadecimal data:
• Address values appear at the start of a frame.
• Write addresses appear in light-blue along with the "W" character.
• Read addresses appear in yellow along with the "R" character.
• Restart addresses appear in green along with the "S" character.
• Data values appear in white.
• "a" indicates Ack (low), "~a" indicates No Ack (high).
• Decoded text is truncated at the end of the associated frame when there is
insufficient space within frame boundaries.
• Pink vertical bars indicate you need to expand the horizontal scale (and run
again) to see decode.
• Red dots in the decode line indicate that more data can be displayed. Scroll or
expand the horizontal scale to view the data.
• Aliased bus values (undersampled or indeterminate) are drawn in pink.