29.3.3.1.1 Compliance to SMBus Specifications

Hardware-Specific Restrictions

Section 2 of the SMBus 2.0 specifications states that powered-down devices must provide no leakage path to ground. There are ESD diodes placed between V_DD and the pads used for SCL and SDA on this device. Assuming V_DD is equivalent to ground when powered down, these ESD diodes provide a path to ground.

Implementation in Software

The following elements of the SMBus 2.0 specifications are not implemented in hardware:

Table 1 of the SMBus 2.0 specifications gives a maximum clock low timeout (T_timeout) of 25-35 ms, which can be implemented by connecting the SCL pin to the TCB peripheral using the Event System. Configure the TCB in Time-Out Check mode with the desired timeout value.
Layer 3 (network layer) features such as packet error checking (PEC), address resolution protocol (ARP). These can be implemented in software if required.