SAMA5D3 Ethernet Development System User’s Guide
DS50002789A-page 18
2018 Microchip Technology Inc.
The MPU requires a 125 MHz reference clock input for its GMAC interface. This is pro-
vided by on-board oscillator Y3. This clock does not need to be supplied by the daugh-
ter board.
Three management interface options are available across the RGMII connector: SPI,
I
2
C, and MDIO/MDC. Check the daughter board documentation to determine which
option(s) it supports, then ensure that both boards are configured for the same man-
agement interface.
On the SAMA5D3 EDS board, the management interface type is selected by jumper
options on Header J4.
shows the jumper settings for each interface option.
TABLE 3-1:
MANAGEMENT INTERFACE SELECTION HEADER J4
Header J4
Board Mode
Management I/F
Jumper pins 2-3
SEL1
I2C
Jumper pins 1-2
SEL2
Open
SEL3
SPI
If the daughter board uses both SPI and MDIO at the same time (which is uncommon),
then use header J4 to select MDIO. SPI would use other non-muxed pins on the RGMII
connector.
Additional signals on the RGMII connector:
•
Reset
. The SAMA5D3 EDS board combines both hardware and software gener-
ated reset signals into one reset signal that is available to the daughter board. The
daughter board may or may not use this reset signal. The hardware reset is gen-
erated at power-on, and can also be generated by pressing the push-button SW1.
The SAMA5D3 can also generate a reset from software via GPIO pin PD19.
•
Interrupt (IRQ_N)
. This is an input to the MPU from the daughter board. It goes to
MPU I/O pin PB28.
•
PME input from the daughter board
. It connects to MPU I/O pin PD17, but the
standard software release may not utilize it.
•
SAMA5D3 GPIO pins PD14, PD15,
and
PD16
are also wired to the RGMII con-
nector and are available for general use.
3.7
RMII EMAC CONNECTOR
J6 is a four-piece, 30-pin connector for connecting an Ethernet daughter board to the
MPU's EMAC interface via RMII. The SAMA5D3 EDS board supplies 3.3V power to the
daughter board. An on-board 50 MHz oscillator provides the RMII REFCLK to both the
MPU and the RMII connector for the daughter board. Separate SPI and MDIO inter-
faces at the connector allow the MPU to manage the daughter board device. The MPU
uses Serial Peripheral Interface 1 (SPI1) with NPCS3 for SPI and the EMAC
MDC/MDIO for MDC/MDIO. See
