5228-DS07-R datasheet(65/100 Pages) BOARDCOM

65 / 100 page

Data Sheet

BCM5228

7/12/04

Broa d c om Co rp o r a t i o n

Document

5228-DS09-405-R

Auxiliary Control/Status Register

Page 53

Edge Rate [1:0]. Control bits used to program the transmit DAC output edge rate in 100BASE-TX mode. These bits are

logically ANDed with the ER [1:0] input pins to produce the internal edge-rate controls (Edge_Rate [1] AND ER [1],

Edge_Rate [0] AND ER [0]).

Auto-Negotiation Indicator. A read-only bit that indicates whether auto-negotiation has been enabled or disabled on the

BCM5228. A combination of a 1 in bit 12 of the Control register and a logic 1 on the ANEN input pin is required to enable

auto-negotiation. When auto-negotiation is disabled, bit 3 of the Auxiliary Control register returns a 0. At all other times, it

returns a 1.

Force100/10 Indication. A read-only bit that returns a value of 0 when one of following two cases is true:

•

The ANEN pin is low AND the F100 pin is low, or

•

Bit 12 of the Control register has been written 0 AND bit 13 of the Control register has been written 0.

When bit 8 of the Auxiliary Control register is 0, the speed of the chip is 10BASE-T. In all other cases, either the speed is

not forced (auto-negotiation is enabled), or the speed is forced to 100BASE-X.

Speed Indication. Bit 1 of the Auxiliary Control register is a read-only bit that shows the true current operation speed of the

BCM5228. A 1 bit indicates 100BASE-X operation, while a 0 indicates 10BASE-T. While the auto-negotiation exchange is

performed, the BCM5228 is always operating at 10BASE-T speed

Full-Duplex Indication. Bit 0 of the Auxiliary Control register is a read-only bit that returns a 1 when the BCM5228 is in full-

duplex mode. In all other modes, it returns a 0.

5228-DS07-R 数据表(PDF) 65 Page - Broadcom Corporation.