General
Review and verify the following for
the custom schematic design:
- Above section, including relevant application
notes and FAQ links
- Pin connectivity requirements (during reset, RX
buffers are enabled. A pullup (4.7kΩ, adjust after
testing) is recommended irrespective of IO
configuration), pin attributes and signal
description
- Electrical characteristics (fail-safe and slew
rate requirements when pulled to 3.3V), timing
parameters and any additional available information
including exceptions
- RC at the input of the
open-drain IOs for slew rate control when pulled to 3.3V
- Attached device address pin connected to IO
supply through a resistor (> 1kΩ)
- Verify the target I2C interface clock rates. The I2C bus
can only be operated as fast as the slowest
peripheral on the bus. If faster operation is
required, move the slow devices to another I2C
port
- Verify that there are no I2C address conflicts on any of
the I2C interface utilized. There are multiple I2C
ports available on the processor, so if a conflict
is seen, move the conflicting devices to a different
I2C bus. If this is not possible, use an I2C bus
switch
- Do not
place more than one set of pullup resistors on the
I2C lines. This can result in excessive loading and
potential incorrect operation. Choose the pullup
value commensurate with the bus speed being
utilized.
- Make sure
that the supply rail powering the processor I2C IO
supply for IO group matches the supply voltage used
for the pullup resistors and the attached I2C
devices. Proper pullup can prevent device damage or
incorrect operation due to voltage mismatch
Schematic Review
Follow the below list for the custom
schematic design:
- WKUP_I2C0 and MCU_I2C0
controllers have dedicated I2C compliant open-drain output type buffers
- Verify the pullup values
used. Compare with the SK schematics or calculate based on the load
- The I2C pullup supply amplitude connected follows
the steady-state maximum voltage at all fail-safe IO
pins requirements. The supply threshold depends on
the supply voltage connected to IO supply for IO
group
- Provision for RC to limit slew rate and RC
values
- Processor VDDSHVx and the attached device IO
sourced from the same supply
- Supply rails connected follow
the ROC
Additional
- Verify recommendations as per the data sheet or
EVM implementation have been considered for the attached
device
- Review the Timing and
switching characteristics, I2C Exceptions section of the data
sheet during the design stage