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
- MCASP interface configuration
and recommended connections (including IOSET)
- Series resistor 22Ω added to
the clock outputs (transmit bit clock, frame sync) near to the processor
clock output pin
- Parallel pull (pulldown for
clock output) added for any of the processor or attached IOs that can
float
- Performance and signal
integrity related concerns have been analyzed when connecting to multiple
attached devices
- Provision for series
resistors added for all the interface signals to minimize reflections or
isolate for testing
Schematic Review
Follow the below list for the custom
schematic design:
- Pullup values used (10kΩ) and
compare with the SK schematics
- Series resistor value used
(22Ω) and the placement (near to processor pin)
- Pullup referenced to the
processor IO supply group VDDSHVx for corresponding MCASP instance and
pins
- Processor IO supply group
VDDSHVx and the attached device IO supply sourced from the same supply
- Supply rails connected follow
the ROC
Additional
- Verify fail-safe operation when
connected to external signals. Applying an external input before supply ramps
can cause voltage feed and affect the processor performance
- Verify the design recommendations
as per the data sheet or EVM implementation have been considered for the
attached device including terminations and external ESD protection
- Two devices can be connected to
MCASP. The recommendation is to follow good or recommended layout practices when
routing the bit clock (transmit bit clock and receive bit clock). Use the IBIS
model to check signal integrity