Datasheet

TSB81BA3D, TSB81BA3DI
IEEE 1394b THREE-PORT CABLE TRANSCEIVER/ARBITER
SLLS559E − DECEMBER 2002 − REVISED JUNE 2006
41
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)
T
CLK_ACTIVATE
CTL1
7 Cycles
Figure 19. 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
T
RESTORE
time, the LLC causes the interface to be initialized and restored to normal operation by
reasserting the LPS signal. (In the above diagram, 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 to 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 7 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 1 of the first 6 cycles of PCLK but to otherwise
place its CTL and D outputs in a high-impedance state. The LLC continues to drive its LREQ output low
during this time.
(c) Receive indicated. Upon the eighth PCLK cycle following reassertion of LPS, the PHY asserts the receive
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 may commence. The
PHY now accepts requests from the LLC via the LREQ line.