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 EVM schematics.
- Series resistor value used (22Ω) and the placement (near to source).
- Pullup referenced to the processor VDDSHVx or VDDSx or VDDS_WKUP for corresponding UART instance and signals.
- Processor VDDSHVx or VDDSx or VDDS_WKUP 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 recommended or allowed.
- 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.