Table 3-21. Ethernet RJ45 Connector J7 Pin Assignment
Pin No.
Signal Name
Signal Description
0
–
Earth ground
1
–
Digital ground
2
ETH0_TXRX_D_N
Media Dependent Interface[3], negative signal of differential pair
3
ETH0_TXRX_D_P
Media Dependent Interface[3], positive signal of differential pair
4
ETH0_TXRX_C_N
Media Dependent Interface[2], negative signal of differential pair
5
ETH0_TXRX_C_P
Media Dependent Interface[2], positive signal of differential pair
6
ETH0_TXRX_B_N
Media Dependent Interface[1], negative signal of differential pair
7
ETH0_TXRX_B_P
Media Dependent Interface[1], positive signal of differential pair
8
ETH0_TXRX_A_N
Media Dependent Interface[0], negative signal of differential pair
9
ETH0_TXRX_A_P
Media Dependent Interface[0], positive signal of differential pair
10
–
–
11
–
Green LED anode
12
–
Green LED cathode
13
–
Yellow LED anode
14
–
Yellow LED cathode
3.4.2
USB Interfaces
The USB (Universal Serial Bus) is a hot-pluggable general-purpose high-speed I/O standard for computer
peripherals. The standard defines connector types, cabling, and communication protocols for interconnecting a wide
variety of electronic devices. The USB 2.0 specification defines data transfer rates as high as 480 Mbps ("high-speed
USB"). A USB host bus connector uses four pins: a power supply pin (5V), a differential pair (D+ and D- pins) and a
ground pin.
The SAMA7G54-EK board features three USB communication ports named USBA, USBB and USBC.
3.4.2.1
USBA Host/Device
The USBA port can act as a USB device or USB host interface and can be accessed via the USB micro-B connector
(J7).
Two resistors (R186 and R188) are placed on its power rail to form a voltage divider, converting 5V into 3.3V voltage
that is then used to indicate the presence of a USB host to the MPU (USBA_VBUSDETECT_PD11).
In the case of board bring-up, USBA is the default port used to connect to the MPU over SAM-BA (SAM Boot
Assistance). For more information, refer to the product
.
The USBA port is also used as a secondary power source, as described in
Power Supply Topology and Power
. In most cases, this port is limited to 500 mA.
SAMA7G54-EK
Function Blocks
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2022 Microchip Technology Inc.
and its subsidiaries
User Guide
DS50003273A-page 43