37.2.4.2.5 I3C Address Arbitration
The Address Header following a Start condition (but not a Restart condition) is subject to
arbitration, meaning multiple devices on the bus may attempt to drive an address on the
bus using SDA lines. The Controller may drive the SDA line to transmit the address of a
device it intends to communicate with. The Target may drive the SDA line to transmit its
own address while requesting for Hot-Join or In-Band
Interrupt. The Address Header Arbitration process is described in Figure 37-11. The Target loses Address Arbitration when
it releases the SDA line to transmit a ‘1
’, but another device on the
bus drives it low to transmit a ‘0
’. Table 37-7
lists all the devices on an I3C bus that can participate in address arbitration and the
different addresses they can drive on the bus.
Device Driving SDA after Start | Address Being Driven on SDA | Representation |
---|---|---|
Active I3C Controller | Broadcast Address/W | I3C SDR transaction |
Dynamic Address/W | I3C Private Write transaction | |
Dynamic Address/R | I3C Private Read transaction | |
Static Address/W | Legacy I2C Write transaction | |
Static Address/R | Legacy I2C Read transaction | |
Secondary I3C Controller (acting as an I3C Target) | Dynamic Address/W | Controller Role Request |
Dynamic Address/R | In-Band Interrupt Request | |
Hot-Join Address/W | Hot-Join Request | |
I3C Target | Dynamic Address/R(1) | In-Band Interrupt Request |
Hot-Join Address/W | Hot-Join Request | |
I2C Target | N/A | N/A |
Note:
|