3.4.1.2 Gigabit Ethernet Interface

The KSZ9131RNX is a completely integrated triple-speed (10BASE-T/100BASE-TX/1000BASE-T) Ethernet physical layer transceiver for transmission and reception of data on standard CAT-5 as well as CAT-5e and CAT-6 unshielded twisted pair (UTP) cables.

The KSZ9131RNX provides the Reduced Gigabit Media Independent Interface (RGMII) for direct connection to RGMII MACs in Gigabit Ethernet processors and switches for data transfers at 10/100/1000 Mbps.

The KSZ9131RNX reduces board cost and simplifies board layout by using on-chip termination resistors for the four differential pairs and by integrating an LDO controller to drive a low-cost MOSFET to supply the 1.2V core.

The KSZ9131RNX offers diagnostic features to facilitate system bring-up and debugging in production testing and in product deployment.

An individual unique 48-bit MAC address (Ethernet hardware address) is allocated to this product and is stored in one of the Microchip 24AA025E48 TWI serial EEPROMs described in Dual Serial EEPROM.

Additionally, for monitoring and control purposes, the RJ45 connectors feature a LED functionality to indicate activity, link, and speed status.

Figure 3-32. Gigabit Ethernet Interface Schematic
Table 3-20. Gigabit Ethernet Interface Schematic
PIOSignal NameShared WithSignal Description
PA15ETH0_TXEN_PA15Transmit enable
PA16ETH0_TX0_PA16Transmit data line 0
PA17ETH0_TX1_PA17Transmit data line 1
PA18ETH0_RXCTL_PA18Receive data valid or carrier sense and data valid
PA19ETH0_RX0_PA19Receive data line 0
PA20ETH0_RX1_PA20Receive data line 1
PA22ETH0_MDC_PA22Management data clock
PA23ETH0_MDIO_PA23Management data input/output
PA24ETH0_TXCK_PA24Transmit clock or 50 MHz reference clock
PA25ETH0_125CK_PA25125 MHz clock
PA26ETH0_TX2_PA26Transmit data line 2
PA27ETH0_TX3_PA27Transmit data line 3
PA28ETH0_RX2_PA28Receive data line 2
PA29ETH0_RX3_PA29Receive data line 3
PA30ETH0_RXCK_PA30Receive clock
PA31ETH0_INT_PA31Ethernet 0 interrupt
Table 3-21. Ethernet RJ45 Connector J7 Pin Assignment
Pin No.Signal NameSignal Description
0Earth ground
1Digital ground
2ETH0_TXRX_D_NMedia Dependent Interface[3], negative signal of differential pair
3ETH0_TXRX_D_PMedia Dependent Interface[3], positive signal of differential pair
4ETH0_TXRX_C_NMedia Dependent Interface[2], negative signal of differential pair
5ETH0_TXRX_C_PMedia Dependent Interface[2], positive signal of differential pair
6ETH0_TXRX_B_NMedia Dependent Interface[1], negative signal of differential pair
7ETH0_TXRX_B_PMedia Dependent Interface[1], positive signal of differential pair
8ETH0_TXRX_A_NMedia Dependent Interface[0], negative signal of differential pair
9ETH0_TXRX_A_PMedia Dependent Interface[0], positive signal of differential pair
10
11Green LED anode
12Green LED cathode
13Yellow LED anode
14Yellow LED cathode