Artesyn COMX-P40x0 ENP2 Installation and Use (January 2015) - Manual (Page 84)

Functional Description
COMX-P40x0 ENP2 Installation and Use (6806800R95C) 84
4.13 PHY
The dTSEC1 interface of FM1 is connected to a BCM5482 Ethernet PHY via RGMII on boards
with the 1GE option. There are two ports included in the PHY but only the first port is used. The
MDIO address for the first port is 0x01 and the second is 0x02.
The MDIO addresses for 4 SGMII PHYs are 0x1C, 0x1D, 0x1E and 0x1F when SerDes option
#5/#6 or #10 is applied (or options #7 or #8 when Bank3 is enabled).
4.14 UART Interface
The P40x0 CPU provides up to four UART ports (Tx and Rx signals) or up to two UART ports with
hardware flow control (Tx, Rx, RTS, and CTS signals). The COMX-P40x0 ENP2 module is
configured by default to route four UART ports to the COM Express connector.
4.15 Real Time Clock
The RTC is implemented by an ST Micro M41T62LC6F device. It is accessed over I2C bus 2 of the
P40x0 CPU at address 0xD0. The RTC provides a 32 KHz clock output to the CPU for
timekeeping and is supplied by the VCC_BAT pin on the COM Express connector.
4.16 Watchdog Timer
The watchdog timer is implemented by an ST Micro M41T65Q65 device. It is accessed over I2C
bus 1 of the P40x0 CPU at address 0xD0. The watchdog timer is capable of generating a power-
on reset and interrupt to the CPU.
4.17 USB
The COMX-P40x0 ENP2 module has one USB port from the CPU connected through an USB
ULPI PHY (USB3315) to a four-port hub (USB2514). The four ports of the hub are routed to the
COM Express connector. The hub is hardware strapped to indicate all ports removable. Two
active-low over-current signals are received from the COM Express connector to the USB hub
to indicate power faults: USB_OC_0_1_N (Port 0 and 1) and USB_OC_2_3_N (Port 2 and 3).