adm6992c Infineon Technologies Corporation, adm6992c Datasheet - Page 20

• Manufacturer Part Number: adm6992c
• Description: Two Port Bridge Fiber To Fast Ethernet Converter
• Manufacturer: Infineon Technologies Corporation

3.2
3.2.1
The Auto Negotiation function provides a mechanism for exchanging configuration information between two ends
of a link segment and automatically selecting the highest performance mode of operations supported by both
devices. Fast Link Pulse (FLP) Bursts provide the signaling used to communicate auto negotiation abilities
between two devices at each end of a link segment. For further details regarding auto negotiation, refer to Clause
28 of the IEEE 802.3u specification. The NINJA C/CX (ADM6992C/CX) supports four different Ethernet protocols,
so the inclusion of auto negotiation ensures that the highest performance protocol will be selected based on the
ability of the link partner.
The auto negotiation function within the NINJA C/CX (ADM6992C/CX) can be controlled either by internal register
access or by the use of configuration pins. If disabled, auto negotiation will not occur until software enables bit 12
in MII Register 0. If auto negotiation is enabled, the negotiation process will commence immediately.
When auto negotiation is enabled, the NINJA C/CX (ADM6992C/CX) transmits the abilities programmed into the
auto negotiation advertisement register at address 04
half duplex, and full duplex modes may be selected. Auto negotiation controls the exchange of configuration
information. Upon successfully auto negotiating, the abilities reported by the link partner are stored in the auto
negotiation link partner ability register at address 05
The contents of the “auto negotiation link partner ability register” are used to automatically configure the highest
performance protocol between the local and far-end nodes. Software can determine which mode has been
configured by auto negotiation, by comparing the contents of register 04
technology whose bit is set in both registers of highest priority relative to the following list:
1. 100Base-TX full duplex (highest priority)
2. 100Base-TX half duplex
3. 10Base-T full duplex
4. 10Base-T half duplex (lowest priority)
The basic mode control register at address 0
negotiation function. When auto negotiation is disabled, the speed selection bit (bit 13) controls switching between
10 Mbps or 100 Mbps operation, while the duplex mode bit (bit 8) controls switching between full duplex operation
and half duplex operation. The speed selection and duplex mode bits have no effect on the mode of operations
when the auto negotiation enabled bit (bit 12) is set.
The basic mode status register at address 1
bit 11), auto negotiation ability (bit 3), and extended register capability (bit 0). These bits are hardwired to indicate
the full functionality of the NINJA C/CX (ADM6992C/CX). The BMSR also provides status on:
•
•
•
The auto negotiation advertisement register at address 04
by the NINJA C/CX (ADM6992C/CX). All available abilities are transmitted by default, but writing to this register
or configuring external pins can suppress any ability.
The auto negotiation link partner ability register at address 05
indicated by auto negotiation communication. The contents of this register are considered valid when the auto
negotiation complete bit (bit 5, register address 1
3.2.2
The twelve sets of four pins listed in
(ADM6992C/CX). The logic states of these pins are latched into the advertisement register (register address 4
Data Sheet
Whether auto negotiation is complete (bit 5)
Whether the Link Partner is advertising that a remote fault has occurred (bit 4)
Whether a valid link has been established (bit 2)
Auto Negotiation and Speed Configuration
Auto Negotiation
Speed Configuration
Table 10
H
indicates the set of available abilities for technology types (bit 15 to
configure the speed capability of each channel of the NINJA C/CX
H
H
) is set.
controls the enabling, disabling and restarting of the auto
H
.
H
20
via FLP bursts. Any combination of 10 Mbps, 100 Mbps,
H
indicates the auto negotiation abilities to be advertised
H
indicates the abilities of the Link Partner as
H
and 05
H
and then selecting the
Function Description
Rev. 1.02, 2005-11-25
ADM6992C/CX
Ninja C/CX
H
)