TLK3131_15 Datasheet, PDF (31/102 Pages) Texas Instruments – Single Channel Multi-Rate Transceiver

TLK3131
www.ti.com
SLLS957A – DECEMBER 2008 – REVISED DECEMBER 2009
2.7.19 MDIO Protocol Timing
The Clause 22 timing required to read from the internal registers is shown in Figure 2-21. The Clause 22
timing required to write to the internal registers is shown in Figure 2-22.
MDC
MDIO
Pu1
0
1
1
0 PA4 PA0 RA4 RA0
0 D15 D0
1
32 "1's"
Preamble
Start
Read
Code
Turn
PHY
REG
Around
Data
Idle
Addr
Addr
(1) Note that the 1 in the Turn Around section is externally pulled up, and driven to Z by TLK3131
Figure 2-21. CL22 – Management Interface Read Timing
MDC
MDIO
0
1
0
1
PA [4:0]
RA 4 RA 0 1
0
D15 D0
1
32 "1's"
Preamble
Start
Write
Code
PHY
REG
Turn
Data
Idle
Addr
Addr
Around
Figure 2-22. CL22 - Management Interface Write Timing
The IEEE 802.3 Clause 22 specification defines many of the registers, and additional registers have been
implemented for expanded functionality.
2.7.20 Clause 22 Indirect Addressing
The TLK3131 Register space is divided into two register groups. One register group can be addressed
directly through Clause 22, and one register group can be addressed indirectly through Clause 22. The
register group which can be addressed through Clause 22 indirectly is implemented in vendor specific
register space (16’h9000 onwards). Due to clause 22 register space limitations, an indirect addressing
method is implemented so that this extended register space can be accessed through clause 22. To
access this register space (16’h9000 onwards), an address control register (Reg 30, 5’h1E) should be
written with the register address followed by a read/write transaction to address data register (Reg 31,
5’h1F) to access the contents of the address specified in address control register. Following timing
diagrams illustrate an example write transaction to Register 16’h9000 using indirect addressing in Clause
22.
MDC
MDIO
0
1
0
1
PA [4:0]
5 'h1 E
1
0 16 'h9000
1
32 "1's"
Preamble
Start
Write
Code
PHY
REG
Turn
Addr
Addr
Around
Data
Idle
Figure 2-23. CL22 – Indirect Address Method – Address Write
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