Datasheet

TSB81BA3D, TSB81BA3DI
IEEE 1394b THREE-PORT CABLE TRANSCEIVER/ARBITER
SLLS559E − DECEMBER 2002 − REVISED JUNE 2006
39
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION (1394a−2000 INTERFACE)
interface reset and disable (continued)
The LLC requests that the interface be reset by deasserting the LPS signal and terminating all bus and request
activity. When the PHY observes that LPS has been deasserted for T
LPS_RESET
, it resets the interface. When
the interface is in the reset state, the PHY sets its CTL and D outputs in the logic 0 state and ignores any activity
on the LREQ signal. Figure 17 shows the timing for interface reset.
PCLK
(a) (c)
(b)
CTL0, CTL1
D0 − D7
LREQ
LPS
(d)
T
LPS_RESET
T
RESTORE
Figure 17. Interface Reset
The sequence of events for resetting the PHY-LLC interface is as follows:
(a) Normal operation. Interface is operating normally, with LPS asserted, PCLK active, status and packet data
reception and transmission via the CTL and D lines, and request activity via the LREQ line. In the above
diagram, the LPS signal is shown as a nonpulsed level signal. However, it is permissible to use a pulsed
signal for LPS in a direct connection between the PHY and LLC; a pulsed signal is required when using an
isolation barrier.
(b) LPS deasserted. The LLC deasserts the LPS signal and, within 1.0 μs, terminates any request or interface
bus activity, places its CTL and D outputs into a high-impedance state, and drives its LREQ output low.
(c) Interface reset. After T
LPS_RESET
time, the PHY determines that LPS is inactive, terminates any interface
bus activity, and drives its CTL and D outputs low. The PHY-LLC interface is now in the reset state.
(d) Interface restored. After the minimum T
RESTORE
time, the LLC may again assert LPS active. When LPS
is asserted, the interface is initialized as described below.
If the LLC continues to keep the LPS signal deasserted, it then requests that the interface be disabled. The PHY
disables the interface when it observes that LPS has been deasserted for T
LPS_DISABLE
. When the interface
is disabled, the PHY sets its CTL and D outputs as stated above for interface reset, but also stops PCLK activity.
The interface is also placed into the disabled condition upon a hardware reset of the PHY. Figure 18 shows the
timing for the interface disable.
When the interface is disabled, the PHY enters a low-power state if none of its ports are active.