Selection Of Gmii Peripheral Components; Circuit Design Around Gmii; Pattern Design Around Gmii - Renesas R-IN32M3 Series User Manual

R-IN32M3 Series: Board design edition
8.1

Selection of GMII Peripheral Components

Select the parts with care to the following.
• Selection of PHY
Full-duplex products IEEE802.3 1000BASE-T.
Parts that have the auto-negotiation function.
Parts with a GMII interface.
Parts that have the auto MDI/MDIX negotiation function.
Operable parts at 125 MHz about MDC clock frequency.
• Selection of the crystal oscillator for PHY
Regarding Jitter and frequency, select the parts to adapt to the requirement of the PHY.
8.2

Circuit Design around GMII

Design the GMII peripheral circuits with care to the following.
• Wiring of GMII
Put the damping resistor of overshoot/undershoot protection.
• For PHY address
Set to the same address as the port number of the R-IN32M3-CL to the PHY address.
Connect the PHY assigned to address 0 to MAC port 0, and connect the PHY assigned to address 1 to MAC port 1.
8.3

Pattern Design around GMII

Design the pattern of GMII peripheral circuits with care to the following.
• Wiring of GMII
The wiring pattern of the signal (GMII) to connect R-IN32M3-CL and PHY should be the shortest. Choose the
thickness of the wiring pattern and signal lines for the pattern to be an impedance of 50Ω.
Do not bend at 45 degrees or less to signal pattern.
For the power/GND pattern, use the wiring with a thick pattern as much as possible.
R18UZ0021EJ0400
Dec. 28, 2018
8. GMII Pins (R-IN32M3-CL Only)
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