14.2.3.2.2 Clock Stretching

The I²C peripherals support the clock stretching feature as defined in Philips I²C v2.1 specifications. This addresses the condition where the I²C slave is unable to meet the clock speed provided by the I²C master and needs to slow down. Care should be taken so that the slowest I²C device does not dominate the bus performance. The I²C slave is allowed to hold down the clock if it needs to reduce the bus speed. The I²C master reads back the clock signal after releasing it to a High state and waits until the line goes High.

Clock stretching is a common practice. However, the total bandwidth of the shared bus might significantly decrease. Estimating the impact of clock stretching is required to share I²C bus among multiple devices.