TLK105 Datasheet, PDF (31/99 Pages) Texas Instruments – Industrial Temp, Single Port 10/100Mbs Ethernet Physical Layer Transceiver

TLK105
TLK106
www.ti.com
SLLSEB8A – AUGUST 2012 – REVISED MARCH 2013
When auto negotiation has started, the TLK10x transmits FLP on one twisted pair and listens on the other,
thus trying to find out whether the other link partner supports the auto negotiation function as well. The
decision on what pair to transmit/listen depends on the MDI/MDI-X state. If the other link partner activates
auto negotiation, then the two parties begin to exchange their information. If the other link partner is a
legacy PHY or does not activate the auto negotiation, then the TLK10x uses the parallel detection
function, as described in IEEE802.3 chapters 40 and 28, to determine 10B-T or 100B-TX operation
modes.
5.4.2 Initialization and Restart
The TLK10x initiates the auto negotiation function if one of the following events have happened:
1. Hardware reset de-assertion
2. Software reset (via register)
3. Auto negotiation restart (via register BMCR (0x0000h) bit 9)
4. Power-up sequence (via register BMCR (0x0000h) bit 11)
The auto-negotiation function is also initiated when the auto-negotiation enable bit is set in register BMCR
(0x0000h) bit 12 and one of the following events has happened:
1. Software restart
2. Transitioning to link_fail state, as described in IEEE802.3
To disable the auto-negotiation function during operation, clear register BMCR (0x0000h) bit 12. During
operation, setting/resetting this register does not affect the TLK10x operation. For the changes to take
place, issue a restart command through register BMCR (0x0000h) bit 9.
5.4.3 Next Page Support
The TLK10x supports the optional feature of the transmission and reception of auto-negotiation additional
(vendor specific) next pages.
If next pages are needed, the user must set register ANAR(0x0004h) bit 15 to '1'. The next pages are then
sent and received through registers ANNPTR(0x0007h) and ANLNPTR(0x0008h), respectively. The user
must poll register ANER(0x0006h) bit 1 to check whether a new page has been received, and then read
register ANLNPTR for the received next page's content. Only after register ANLNPTR is read may the
user write to register ANNPTR the next page to be transmitted. After register ANNPTR is written, new next
pages overwrite the contents of register ANLNPTR.
If register ANAR(0x0004h) bit 15 is set, then the next page sequence is controlled by the user, meaning
that the auto-negotiation function always waits for register ANNPTR to be written before transmitting the
next page.
If additional user-defined next pages are transmitted and the link partner has more next pages to send, it
is the user's responsibility to keep writing null pages (of value 0x2001) to register ANNPTR until the link
partner notifies that it has sent its last page (by setting bit 15 of its transmitted next page to zero).
5.5 Link Down Functionality
The TLK10x includes advanced link-down capabilities that support various real-time applications. The link-
down mechanism of the TLK10x is configurable and includes enhanced modes that allow extremely fast
reaction times to link-drops.
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