TSB81BA3 datasheet(28/57 Pages) TI

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TSB81BA3, TSB81BA3I

IEEE 1394b THREEPORT CABLE TRANSCEIVER/ARBITER

SLLS559B − DECEMBER 2002 − REVISED OCTOBER 2003

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION (1394a−2000 INTERFACE)

The TSB81BA3 is designed to operate with an LLC such as the Texas Instruments TSB12LV21B, TSB12LV26,

TSB12LV32, TSB42AA4, or TSB12LV01B when the BMODE terminal is tied low. Details of operation for the

Texas Instruments LLC devices are found in the respective LLC data sheets. The following paragraphs describe

the operation of the PHY-LLC interface. This interface is formally defined in IEEE 1394a−2000, Section 5A.

The interface to the LLC consists of the PCLK, CTL0−CTL1, D0−D7, LREQ, LPS, and LKON/DS2 terminals on

the TSB81BA3, as shown in Figure 10.

LKON/DS2

LPS

PCLK (SYSCLK)

LREQ

D0–D7

CTL0–CTL1

Link-Layer

Controller

TSB81BA3

Figure 10. PHY-LLC Interface

The PCLK terminal provides a 49.152-MHz interface system clock. All control and data signals are synchronized

to, and sampled on, the rising edge of PCLK. This terminal serves the same function as the SYSCLK terminal

of 1394a−2000 compliant PHY devices.

The CTL0 and CTL1 terminals form a bidirectional control bus, which controls the flow of information and data

between the TSB81BA3 and LLC.

The D0−D7 terminals form a bidirectional data bus, which transfers status information, control information, or

packet data between the devices. The TSB81BA3 supports S100, S200, and S400 data transfers over the

D0−D7 data bus. In S100 operation only the D0 and D1 terminals are used; in S200 operation only the D0−D3

terminals are used; and in S400 operation all D0−D7 terminals are used for data transfer. When the TSB81BA3

is in control of the D0−D7 bus, unused Dn terminals are driven low during S100 and S200 operations. When

the LLC is in control of the D0−D7 bus, unused Dn terminals are ignored by the TSB81BA3.

The LREQ terminal is controlled by the LLC to send serial service requests to the PHY in order to request access

to the serial-bus for packet transmission, read or write PHY registers, or control arbitration acceleration.

The LPS and LKON/DS2 terminals are used for power management of the PHY and LLC. The LPS terminal

indicates the power status of the LLC, and may be used to reset the PHY-LLC interface or to disable PCLK. The

LKON/DS2 terminal sends a wake-up notification to the LLC or external circuitry and indicates an interrupt to

the LLC when either LPS is inactive or the PHY register L bit is 0.

The TSB81BA3 normally controls the CTL0−CTL1 and D0−D7 bidirectional buses. The LLC is allowed to drive

these buses only after the LLC has been granted permission to do so by the PHY.

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