Microchip Technology SAMA5D3 XPLAINED, Руководство пользователя

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Board Details and Configuration
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2018 Microchip Technology Inc. DS50002789A-page 17
3.6 RGMII/MII GMAC CONNECTOR
This connector allows a daughter board to be connected to the GMAC port of the
SAMA5D3. (See
Figure 3-2 .) The daughter board is a Microchip evaluation board for
an Ethernet PHY or an Ethernet switch. This interface is used primarily for RGMII, and
the supplied software operates it as RGMII. This GMAC can also operate as MII, but
this is a secondary option that is not necessarily supported by the pre-installed soft-
ware. Daughter boards may support only RGMII, only MII, or both RGMII and MII, so
check the daughter board documentation for details.
FIGURE 3-2: RGMII CONNECTOR
A daughter board receives power from the SAMA5D3 EDS board via any of the avail-
able supplies: VDDIOP1 (VARIO), 2V5, 3V3, 5V, or 12V. The daughter board documen-
tation specifies which power rail(s) are used. Jumpers J3, J7, J13, and J17 are used to
connect/disconnect 12V, 5V, 3V3, and 2V5 to this connector. Normally, all of these
jumpers should be installed even if some voltages are not needed by the daughter
board.
Header J2 is used to select the voltage for VDDIOP1: either 3.3V, 2.5V, or 1.8V. (Refer
to
Figure 3-3 .) Except for the two I
2
C signals, all the signals on this connector operate
at I/O voltage VDDIOP1. The I
2
C signals operate at 3.3V, independent of VDDIOP1.
The VDDIOP1 must be set at 3.3V whenever the SD card or the I
2
C is used. Daughter
boards may or may not use VDDIOP1 supplied from the SAMA5D3 board. All daughter
boards are compatible with VDDIOP1 = 3.3V, but not necessarily with 2.5V or 1.8V.
Check the daughter board documentation for I/O voltage compatibility and possible
configuration details.
FIGURE 3-3: VDDIP (VARIO) VOLTAGE SELECT
Three indicator LEDs make it easy to visually verify the VDDIOP1 (VARIO) voltage:
• D10: Green = 3.3V
• D11: Yellow = 2.5V
• D12: Blue = 1.8V