General
Review and verify the following for
the custom schematic design:
- Above section, including relevant application
notes and FAQ links
- Pin attributes and signal
description
- Electrical characteristics,
timing parameters, and any additional available information
- Provision for series
resistors near to source added for all the interface signals to minimize
reflections or isolate for testing
- Parallel pull added for any
of the processor or attached IOs that can float
- Interface signal polarity and
connection
- External ESD protection when
the interface signals are connected directly to external inputs
- Required speed, programmed
Baud rate versus supported baud rate, and required versus calculated error
due to clock divider mismatch
Schematic Review
Follow the below list for the custom
schematic design:
- Pullup values used (10kΩ or similar) and compare
with the SK schematics.
- Series resistor value used
(22Ω) and the placement (near to source).
- Pullup referenced to the processor VDDSHVx for
corresponding UART instance and signals.
- Processor VDDSHVx and the attached device IO
supply sourced from the same supply.
- Processor IOs are not fail-safe. Applying an
input before the processor supply ramps is not
allowed or recommended.
- Supply rails connected follow
the ROC.
Additional
- Verify fail-safe operation when connected to
external interface signals. Applying an external input
signal before processor supply ramps can cause voltage feed
and can affect the custom board functions.
- Verify recommendations as per the data sheet or
EVM implementation have been considered for the attached
device including terminations and external ESD
protection.