RTL8208B Ver la hoja de datos (PDF) - Realtek Semiconductor

Número de pieza

componentes Descripción

Lista de partido

RTL8208B

SINGLE-CHIP OCTAL 10/100BASE-TX/FX PHY TRANSCEIVER

Realtek Semiconductor 

RTL8208B-LF/RTL8208BF-LF

Datasheet

Loopback – The RTL8208B(F)-LF may be placed into loopback mode by writing a ‘1’ to bit 14.

Loopback mode may be cleared either by writing a ‘0’ to bit 14 or by resetting the chip. When this bit is

read, it will return a ‘1’ when the chip is in software-controlled loopback mode, otherwise it will return a

‘0’.

Speed Selection – If auto negotiation is enabled, this bit has no effect on the speed selection. However, if

auto negotiation is disabled using software control, the operating speed of the RTL8208B(F)-LF can be

forced by writing the appropriate value to bit 13. Writing a ‘1’ to this bit forces 100Base-X operation,

while writing a ‘0’ forces 10Base-T operation. When this bit is read, it returns the value of the

software-controlled forced-speed selection only.

Auto Negotiation Enable – Default is auto negotiation enabled for all TP ports, and disabled for FX

ports. Auto negotiation can be disabled via software control by setting 0.12=0.

Power Down – The RTL8208B(F)-LF supports a low power mode. Writing a ‘1’ will enable power down

mode, and writing a ‘0’ will return the RTL8208B(F)-LF to normal operation. When read, this register

will return a ‘1’ when in power down mode, and a ‘0’ during normal operation.

Isolate – Each PHY may be isolated from its MII by writing a ‘1’ to bit 10. All MII outputs will be tri-

stated and all MII inputs will be ignored. Since the MII management interface is still active, the isolate

mode may be cleared either by writing a ‘0’ to bit 10 or by resetting the chip. When this bit is read, it will

return a ‘1’ when the chip is in isolate mode, and return a ‘0’ during normal operation.

Restart Auto Negotiation – Bit 9 is a self-clearing bit that allows the auto negotiation process to be

restarted, regardless of the status of the auto negotiation state machine. In order for this bit to have an

effect, auto negotiation must be enabled. Writing a ‘1’ to this bit restarts auto negotiation. Writing a ‘0’ to

this bit has no effect. When this bit is read, it will always return a ‘0’.

Duplex Mode – By default, the RTL8208B(F)-LF powers up in half duplex mode. The chip can be

forced into full duplex mode by writing a ‘1’ to bit 8 while auto negotiation is disabled. Half duplex mode

can be resumed either by writing a ‘0’ to bit 8 or by resetting the chip. When NWay is enabled, this bit

reflects the results of auto negotiation, and is in read-only mode. When NWay is disabled, this bit can be

set through the SMI, and is in Read/Write mode. When 100FX is enabled, this bit can be set through the

SMI or FX_DUPLEX pin and is in Read/Write mode.

Reserved Bits – All reserved MII register bits must be written as ‘0’ at all times. Ignore the

RTL8208B(F)-LF output when these bits are read.

Single-Chip Octal 10/100-TX/FX PHY Transceiver

15

Track ID: JATR-1076-21 Rev. 1.3

Share Link: