Yes, most Legacy I²C Target devices can be operated on an I3C Bus, provided they have a 50 ns spike (glitch) filter and do not attempt to stall the clock. Such use will not degrade the speed of communications to I3C Targets; it will require decreased speed only when communicating with the I²C Targets.

I3C supports Legacy I2C Target devices using Fast-mode (Fm, 400 KHz) and FastMode+ (Fm+, 1 MHz) with the 50 ns spike filter, but not the other I2C modes, and not I2C devices lacking the spike filter, or I2C devices that stretch the clock.

FAQ Type: 
I3C