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 VDD and the pads used for SCL and SDA on this
device. Assuming VDD 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 (Ttimeout) 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.