MIPI I3C Protocol Support

Embedded Systems

MIPI Improved Inter-Integrated Circuit

What is MIPI I3C?

MIPI I3C (Improved Inter-Integrated Circuit) is a high-performance sensor interface specification developed by the MIPI Alliance as a successor to I2C and SPI for sensor and actuator communication. I3C maintains backward compatibility with I2C devices on the same bus while offering significantly higher data rates — up to 12.5 MHz in SDR (Single Data Rate) mode and up to 100 MHz in HDR (High Data Rate) modes including HDR-DDR, HDR-TSP, and HDR-TSL. Like I2C, I3C uses just two wires (SDA and SCL) but adds powerful features including dynamic address assignment, in-band interrupts (eliminating dedicated IRQ lines), hot-join capability, and a standardized command code interface. I3C is gaining rapid adoption in smartphones, wearables, IoT devices, laptops, and automotive sensor systems where designers need higher bandwidth, lower pin count, and lower power consumption compared to legacy I2C and SPI interfaces. Protocol analysis for I3C is essential due to the protocol's complexity — engineers must verify dynamic address assignment sequences, validate HDR mode transitions, debug in-band interrupt handling, and ensure backward compatibility with legacy I2C devices sharing the bus. The multi-mode operation and advanced features make I3C significantly more complex to debug than I2C, making a dedicated protocol analyzer invaluable.

MIPI I3C Quick Reference

type Serial, synchronous
signals SDA, SCL
max Speed 12.5 MHz SDR / 25 MHz HDR
voltage Range 1.2V – 1.8V
addressing Dynamic addressing

Acute Instruments Supporting MIPI I3C

Recommended Solutions

Recommended for Decode

TB3016F

TB3016F

With Analog Channels

MSO2116E

MSO2116E

With Electrical Validation

MSO3124V

MSO3124V

All Supporting Products

Protocol Decode
Hardware Trigger
Electrical Validation
Protocol Exerciser

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How to Analyze MIPI I3C with Acute Instruments

1

Connect your Acute logic analyzer to the SDA and SCL lines of the I3C bus.

2

Attach a ground lead to the target board's ground reference.

3

In the Acute software, select the MIPI I3C protocol decoder and assign SDA and SCL to the corresponding channels.

4

Configure the decoder for the expected operating modes (SDR, HDR-DDR, etc.) and I3C specification version.

5

Capture and view decoded transactions including Common Command Codes (CCCs), dynamic address assignments, in-band interrupts, and HDR data transfers with full timing analysis.

Frequently Asked Questions

What sample rate do I need for MIPI I3C?
For SDR mode at 12.5 MHz, sample at a minimum of 50 MHz (4x the clock rate). For HDR-DDR mode, where data transitions occur on both clock edges, use at least 200 MHz to accurately capture double-data-rate signaling. Acute logic analyzers with 2 GHz timing analysis provide excellent margin for even the fastest I3C HDR modes.
Why does my I3C decoder show errors during HDR mode transfers?
HDR mode transitions are a common source of decode errors. Ensure the sample rate is high enough for the HDR data rate, and verify that the decoder is configured to recognize HDR entry and exit patterns. Signal integrity is more critical in HDR modes — check that probe loading is minimal and that the logic analyzer threshold is set appropriately for the I3C signal swing.
How many channels are needed for I3C analysis?
I3C requires 2 channels — one for SDA and one for SCL, identical to I2C. If you are analyzing a bus with both I3C and legacy I2C devices, no additional channels are needed since they share the same physical lines. For monitoring in-band interrupt responses alongside other system signals, additional channels may be useful.

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