General
Review and verify the
following for the custom schematic design:
- Reviewed above "Common checklist for all
sections" section of the user's guide.
- MAC interface configuration for CPSW3G0 and PRU-ICSSG0,
PRU-ICSSG1
- Series
resistors on the TDx signals and EPHY RDx
signals
- IO level compatibility between processor MAC interface
signals and EPHY (attached device).
- MAC-to-MAC interface connections
- Matching of processor and EPHY clock specifications.
- Clocking of EPHY and processor MAC for RMII interface.
- MDIO interface and EPHY address configuration.
- Implementation of EPHY reset logic.
- Implementation of x2 EPHYs reset logic.
- Ethernet interface IOSET combination
- Pullup on the MDIO interface MDC (clock signal) can be
optional (EPHY can have internal pulldown; the
recommendation is to verify the availability of pull
in the EPHY data sheet).
Schematic Review
Follow the below list for the custom schematic
design:
- The recommendation is to compare the bulk and decoupling
capacitors used for process and the EPHy supply
rails with EVM or SK schematic implementation (when
TI EPHY is used).
- Supply rails connected follow the ROC
- CPSW3G0 supports RGMII and RMII configuration.
PRU-ICSSG, PRU-ICSSG1 supports RGMII and MII
- Provision
for series resistor for the processor MAC transmit
signals TDx close to the processor MAC TDx output
pins have been provided and initial value (0Ω) is
used. Optional 0Ω series resistors close to the
attached device for the RDx signals can be
implemented.
- IO level compatibility between processor MAC and EPHY
(attached device). The attached device IO supply and
the IO supply for IO group VDDSHV1 or VDDSHV2
referenced by the interface signals are recommended
to be connected to the same supply source.
- Compare the bulk and decoupling capacitors used for all
the EPHY supply rails with EVM or SK schematics when
TI EPHY is used
- When MAC-to-MAC interface is used, the recommendation is
to verify IO level compatibility, fail-safe
operation (when x2 processor MACs are referenced to
(powered by) different power sources) and matching
of clock specifications.
- A crystal with internal oscillator or an external
oscillator for each EPHy or a common external
oscillator with buffers (outputs are use case
dependent) can be used.
- The recommendation is to match the EPHy and the
processor clock specifications.
- Clocking of EPHy and processor MAC for RMII interface
including addition of buffers (based on the EPHY
configuration) and clock architecture (use of common
Oscillator and Buffer with multiple outputs). In
case processor clock output is connected to more
than one input, each of the clock input is
recommended to be the buffered output of the clock.
- Connection of the RMII clock when 2 x interface is used
(clock pin is common)
- MDIO
interface connection including pullup (2.2kΩ (Follow
EPHY recommendations)) for MDIO data signal added
near to the EPHY. MDIO connection to multiple x2
devices and the addition of pullup near each EPHY.
When more than x1 EPHY are used, configuration of
EPHY address for MDIO interface. CPSW3G0, PRU-ICSSG0
and PRU-ICSSG1 instances include dedicated MDIO
interface. Make sure the Ethernet interface MDIO
connection maps to the right MDIO interface.
- The recommendation is to verify the EPHY reset
implementation including ANDing logic, AND gate
input pullup and EPHY reset input pull with the EVM
or SK implementation when TI EPHY is used. A 3-input
ANDing logic can be used to implement the attached
device (EPHY) reset. Processor GPIO (used to locally
reset the EPHY) is connected as one of the input to
the ANDing logic AND gate with provision for pullup
(10kΩ or 47kΩ) (to support boot) near to the ANDing
logic AND gate input and provision for 0Ω to isolate
the GPIO output for testing or debug. The other two
inputs to the AND gate are the MAIN domain POR (cold
reset) status output (PORz_OUT) and MAIN domain warm
reset status output (RESETSTATz).
- When more than one (x2) EPHy are used, the
recommendation is to provide provision to reset the
EPHy individually.
- RMII interface includes IOSET combination. When the RMII
interface is configured, the recommendation is to
follow the IOSET including the common RMII clock
when 2 x RMII interfaces are connected. The Ethernet
interface timing is closed for IOSETS. Mixing of
signals between IOSETS is not recommended.
Additional
- The recommendation is to follow the steps below recommended when
TI EPHY is used:
- Obtain a review of the implementation done with
the EPHY business unit or product line.
- The recommendation is to verify recommended bulk
and decoupling capacitors are added and the power
sequence requirements are followed.
- The recommendation is to verify RBIAS resistor
value & tolerance, selection of the RJ45
connector, external ESD protection provision for
MDI signals and connection of RJ45 connector
shield to circuit ground
- The recommendation is to use a single output, individual buffer
device, or dual or multiple output buffer to connect the
clock output of the oscillator to the processor and EPHYs.
For specific use case (requirement for some of the
industrial applications using a Time Sensitive Networking
(TSN)) input and two or more output (based on number of
EPHYs used) buffer is recommended for the processor and the
EPHYs.
- When EPHY is configured as an RMII slave (peripheral), a
two-output phase aligned buffer with a common input is
recommended
- If space is not a constraint, consider adding 0Ω series
resistors on the RX signals close to the EPHY
- ANDing logic additionally performs IO level translation. Verify
the reset IO level compatibility before optimizing the reset
ANDing logic. IO level mismatch can cause supply leakage and
affect processor operation.
- To simplify the ANDing logic, use a dual input AND gate with
RESETSTATz and the processor GPIO as inputs.
- Verify recommendations as per the data sheet or EVM
implementation are considered for the attached device,
including terminations and external ESD protection.
- Interchanging the MDIO interface for the CPSW3G0, PRU-ICSSG0 and
PRU-ICSSG1 Ethernet interfaces is currently not
supported.
- In case Ethernet boot is considered, the recommendation is to
review the silicon errata, verify the supported EPHY
interface configurations, MAC interface port used versus
recommended, and the recommended clock and interface
connection.