Actiphy Power Management; Figure 2.2 Actiphy State Diagram - Renesas R-IN32M4-CL2 User Manual

R-IN32M4-CL2 User's Manual Gigabit Ethernet PHY Edition
2.2

ActiPHY Power Management

In addition to the IEEE-specified power-down control bit (device register bit 0.11), the GbE-PHY also includes an
ActiPHY power management mode for each PHY. This mode enables support for power-sensitive applications. It utilizes
a signal-detect function that monitors the media interface for the presence of a link to determine when to automatically
power-down the PHY. The PHY wakes up at a programmable interval and attempts to wake up the link partner PHY by
sending a burst of fast link pulse over copper media.
The ActiPHY power management mode is enabled on a per-port basis during normal operation at any time by setting
register bit 28.6 to 1.
The following operating states are possible when ActiPHY mode is enabled:
• Low power state
• Link partner wake-up state
• Normal operating state (link-up state)
The GbE-PHY switches between the low power state and link partner wake- up state at a programmable rate until
signal energy has been detected on the media interface pins. When signal energy is detected, the PHY enters the normal
operating state. If the PHY is in its normal operating state and the link fails, the PHY returns to the low power state after
the expiration of the link status time-out timer. After reset, the PHY enters the low power state.
When autonegotiation is enabled in the PHY, the ActiPHY state machine operates as described.
When autonegotiation is disabled and the link is forced to use 10BASE-T or 100BASE-TX modes while the PHY is in
its low power state, the PHY continues to transition between the low power and link partner wake-up states until signal
energy is detected on the media pins. At that time, the PHY transitions to the normal operating state and stays in that state
even when the link is dropped. When autonegotiation is disabled while the PHY is in the normal operation state, the PHY
stays in that state when the link is dropped and does not transition back to the low power state.
The following illustration shows the relationship between ActiPHY states and timers.
FLP Burst
LP Wake-up
State

Figure 2.2 ActiPHY State Diagram

R18UZ0043EJ0100
Mar 4, 2016
Low Power State
Sleep Timer Expires
Timeout Timer Expires and
Auto-negotiation Enabled
2. Functional Descriptions
Signal Energy Detected on
Media
Normal
Operation State
Page 5 of 39