Technical data

If the PowerOn reset is used, the PHYs are active after reset; if RES_PHY_N is used, the PHYs

remain in power down mode after reset and must subsequently be activated with the PowerDown

bit in the Basic Control register. The HW reset must be present for at least 100 µs. These reset

signals are internally extended by 5.2 ms to ensure that the PHY is properly reset. All analog

circuits and all digital logic including management registers are initialized. After initialization, the

respective PWRUPRST signal in the PHY_STATUS register is set.

Notes: 1. During the hardware reset and its extension, the clock signal for the PHYs must be

supplied.

2. A hardware reset is commonly issued to both PHYs.

(b) Software reset

Resetting the PHYs core can also be accomplished by setting the Reset bit in the respective

Basic Control register to 1

. This signal is self-clearing. After the register has been written, the

internal software reset is extended by 256 µs for PLL stabilization before the logic is released

from reset. A software reset affects the PHY registers and resets them to their initial values

except where noted.

Note: A software reset can be issued separately for each PHY.

When the PHYs come out of software and energy detect power down, they are automatically acti-

vated. After exiting the power down mode, the PHY-internal power-down reset is extended by

256 µs for PLL stabilization before logic is released from reset.

Note: This PHY-internal power down reset does not affect the PHY management registers.

(7) Half/Full Duplex

In half duplex mode, stations contend for the use of the physical medium, using the CSMA/CD algo-

rithms specified. Half duplex mode is required on those media that are not capable of supporting

simultaneous transmission and reception without interference like 10BASE-2 and 100BASE-T4.

The full duplex operation mode can be used when all of the following conditions are fulfilled:

<1> The physical medium is capable of supporting simultaneous transmission and recep-

tion without interference.

<2> There are exactly two stations on the LAN. This allows the physical medium to be

treated as a full duplex point-to-point link between the stations.

<3> Both stations on the LAN are capable of and have been configured to use full duplex

operation.

Technical data subject to change Version 1.0.0