TSB41AB3IPFP datasheet(34/52 Pages) TI

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TSB41AB3

IEEE 1394a2000 THREEPORT CABLE TRANSCEIVER/ARBITER

SLLS418I − JUNE 2000 − REVISED DECEMBER 2004

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

LLC service request (continued)

The 3-bit request speed field used in bus requests is shown in Table 15.

Table 15. Bus Request Speed Encoding

LR4-LR5

DATA RATE

000

S100

010

S200

100

S400

All others

Invalid

NOTE:

The TSB41AB3 accepts a bus request with an invalid speed code and process the bus request

normally. However, during packet transmission for such a request, the TSB41AB3 ignores any data

presented by the LLC and transmits a null packet.

For a read register request the length of the LREQ bit stream is 9 bits as shown in Table 16.

Table 16. Read Register Request

BIT(s)

NAME

DESCRIPTION

Start bit

Indicates the beginning of the transfer (always 1)

1-3

Request type

A 100 indicating this is a read register request

4-7

Address

Identifies the address of the PHY register to be read

Stop bit

Indicates the end of the transfer (always 0)

For a write register request the length of the LREQ bit stream is 17 bits as shown in Table 17.

Table 17. Write Register Request

BIT(s)

NAME

DESCRIPTION

Start bit

Indicates the beginning of the transfer (always 1)

1-3

Request type

A 101 indicating this is a write register request

4-7

Address

Identifies the address of the PHY register to be written to

8-15

Data

Gives the data that is to be written to the specified register address

Stop bit

Indicates the end of the transfer (always 0)

For an acceleration control request the Length of the LREQ data stream is 6 bits as shown in Table 18.

Table 18. Acceleration Control Request

BIT(s)

NAME

DESCRIPTION

Start bit

Indicates the beginning of the transfer (always 1)

1-3

Request type

A 110 indicating this is an acceleration control request

Control

Asynchronous period arbitration acceleration is enabled if 1, and disabled if 0

Stop bIt

Indicates the end of the transfer (always 0)

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