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 (simulated) 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 or similar) and compare
with the SK schematics
- Series resistor value used
(22Ω) and the placement (near to processor pin)
- Pullup referenced to the processor VDDSHVx for
corresponding MCASP instance and pins
- Processor 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 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
- 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). Perform simulations using IBIS
model