TSB41BA3ATPFPEP datasheet(49/68 Pages) TI2

49 / 68 page

TSB41BA3A-EP

IEEE 1394b THREE-PORT CABLE TRANSCEIVER/ARBITER

SGLS253B—OCTOBER 2004—REVISED MAY 2011

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION (1394a-2000 INTERFACE)

interface reset and disable (continued)

SYSCLK

ISO

(high)

(a)

(c)

(b)

CTL0

D0 − D7

LREQ

LPS

(d)

tCLK_ACTIVATE

CTL1

7 Cycles

Figure 21. Interface Initialization

The sequence of events for initialization of the PHY-LLC is as follows:

(a) LPS reasserted. After the interface has been in the reset or disabled state for at least the minimum tRESTORE

time, the LLC causes the interface to be initialized and restored to normal operation by reasserting the LPS

signal. (In Figure 21, the interface is shown in the disabled state with PCLK low inactive. However, the

interface initialization sequence described here is also executed if the interface is merely reset but not yet

disabled.)

(b) PCLK activated. If the interface is disabled, then the PHY reactivates its PCLK output when it detects that

LPS has been reasserted. If the PHY has entered a low-power state, then it takes between 5.3 ms and

7.3 ms for PCLK to be restored; if the PHY is not in a low-power state, then the PCLK is restored within 60

ns. The PCLK output is a 50% duty cycle square wave with a frequency of 49.152 MHz ±100 ppm (period

of 20.345 ns). During the first seven cycles of PCLK, the PHY continues to drive the CTL and D terminals

low. The LLC is also required to drive its CTL and D outputs low for one of the first six cycles of PCLK but

otherwise to place its CTL and D outputs in a high-impedance state. The LLC continues to drive its LREQ

output low during this time.

state on the CTL lines and the data-on indication (all 1s) on the D lines for one or more cycles.

(d) Initialization complete. The PHY asserts the idle state on the CTL lines and logic 0 on the D lines. This

indicates that the PHY-LLC interface initialization is complete and normal operation can commence. The

PHY now accepts requests from the LLC via the LREQ line.

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