Easyi3C is a leading supplier of embedded system tools that simplify the development and debugging of various communication protocols. The company offers a range of products designed to help engineers and developers use I3C/I2C , USB and MIPI, JEDEC, MCTP and other protocols more efficiently.

Verify chip IBI function based on Tower I3C Host Adapter

1. Theoretical Preparation

In-Band Interrupt (IBI) is an important feature in the I3C protocol that allows slave devices to send interrupt requests to the master device without adding additional interrupt lines.

1. Basic Concepts of In-Band Interrupt (IBI)

     a. Definition and Working Principle:

        1) IBI is an interrupt mechanism defined in the I3C protocol. The slave device sends an interrupt request to the master device by pulling down the SDA line (when there is no start signal on the SCL line).

        2) The master device initiates an IBI transaction within 5μs after detecting that SDA is pulled low (SCL is high).

        3) Supports multiple slave devices to send interrupt requests at the same time. The master device arbitrates through the slave address, and the lower address responds first.

    b. Technical advantages:

        1) Compared to I2C, it avoids the need for an additional interrupt line

        2) Support interrupt notification for hot-plug devices

        3) Share bus resources with normal data transmission to improve efficiency‌

2. I3C's in-band interrupt mechanism is significantly improved compared to traditional I2C interrupts:

2. Tower I3C Host Adapter IBI Test Steps

With the above theoretical preparation, it is easier to understand the functional characteristics of IBI. Next, we can perform IBI testing of I3C through the Tower I3C Host Adapter.

1. Hardware Preparation:

   1) Connect the I3C Host Adapter to the host via USB;

   2) Install the official driver and supporting software (Easyi3C Tower Console GUI);

   3) Connect the slave device to be tested to the I3C interface of the adapter.

2. Perform IBI testing via the Tower Console GUI:

Simple tests can be performed through the GUI, which is simple and easy to use. You can refer to the following example test process.

This test uses a temperature sensor on a DDR5 to test IBI. According to the chip's SPEC:

As defined in the spec above, we configure MR27 (0x1b) to enable the chip's IBI, and then set MR29 (0x1d) to 0. This will trigger a temperature alarm at normal laboratory temperatures, thereby triggering the IBI signal and making it visible on the I3C bus.

According to the above SPEC definition, if we follow the following operations, we will see the IBI on the bus, thereby verifying the functional correctness of the IBI.

a. Enable IBI, this is to enable the Tower I3C Host Adapter IBI function.

b. Send SETAASA, then write MR29 (0x1d) to 0 under I3C. This will trigger the temperature alarm at normal laboratory temperature.

c. Under I3C, write MR27 (0x1b) to 0x0f to enable the IBI of the chip.

d. Send CCC, ENEC.

e. At this time, the following IBI interrupt signal will appear on the oscilloscope.

3. IBI testing via Python script:

In more complex automated testing scenarios, we can perform IBI testing through Python scripts. For example, by inserting a Parity Error, we can trigger the Slave to initiate IBI. IBI also has more complex configurations that can be set through related APIs to meet different testing requirements.

IBI-related APIs are as follows:

For more details, please visit the official website and download the User Manual of the relevant product to understand the definition and usage of the relevant API.

By using the above API, combined with some APIs for plug-in errors, we can automatically test the IBI function of our related chips.

3. Summary

Through the above introduction, using the Tower I3C Host Adapter, you can easily test the IBI function of I3C. IBI is an important new feature of the I3C protocol. Only after passing the above test can the chip be safely shipped to customers.