Artesyn COMX-P40x0 ENP2 Installation and Use (August 2014) - Manual (Page 73)

Functional Description
COMX-P40x0 ENP2 Installation and Use (6806800R95B) 73
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 4 simple UART ports (Tx and Rx signals) or up to 2 UART ports
with hardware flow control (Tx, Rx, RTS, and CTS signals). The COMX-P40x0 ENP2 is configured
by default to route 4 simple 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 a 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 overcurrent 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).