VSC8601 Datasheet
Functional Descriptions
The following illustration shows the relationship between ActiPHY states and timers.
Figure 7.
ActiPHY State
Low-Power State
Signal Energy Detected on
FLP Burst
Signal Sent
Media
Sleep Timer Expires
Timeout Timer Expires and
Auto-Negotiation Enabled
LP Wake-up
State
Normal
Operation
3.10.1
Low-Power State
In the low-power state, all major digital blocks are powered down. However, the
following functionality is provided:
•
•
SMI interface (MDC, MDIO, MDINT)
CLKOUT
In this state, the PHY monitors the media interface pins for signal energy. The PHY
comes out of low-power state and transitions to the normal operating state when signal
energy is detected on the media. This happens when the PHY is connected to one of the
following:
•
•
•
Auto-negotiation capable link partner
Auto-negotiation incapable (blink/forced) link partner (100BASE-TX or 10BASE-T)
Another PHY in ActiPHY LP wake-up state
In the absence of signal energy on the media pins, the PHY transitions from the
low-power state to the LP wake-up state periodically based on the programmable sleep
timer (register bits 20E.14:13). The actual sleep time duration is randomized from
–80 ms to +60 ms to avoid two linked PHYs in ActiPHY Mode entering a lock-up state
during operation.
Revision 4.1
September 2009
Page 24
VITESSE [ VITESSE SEMICONDUCTOR CORPORATION ]
