LAN9313 Datasheet, PDF (97/398 Pages) SMSC Corporation – Three Port 10/100 Managed Ethernet Switch with MII

Three Port 10/100 Managed Ethernet Switch with MII
Datasheet
Note: The power-down modes of each PHY (Port 1 PHY and Port 2 PHY) are controlled
independently.
Note: The PHY power-down modes do not reload or reset the PHY registers.
7.2.9.1
PHY General Power-Down
This power-down mode is controlled by bit 11 of the Port x PHY Basic Control Register
(PHY_BASIC_CONTROL_x). In this mode the entire PHY, except the PHY management control
interface, is powered down. The PHY will remain in this power-down state as long as bit 11 is set.
When bit 11 is cleared, the PHY powers up and is automatically reset.
7.2.9.2
PHY Energy Detect Power-Down
This power-down mode is enabled by setting bit 13 (EDPWRDOWN) of the Port x PHY Mode
Control/Status Register (PHY_MODE_CONTROL_STATUS_x). When in this mode, if no energy is
detected on the line, the entire PHY is powered down except for the PHY management control
interface, the SQUELCH circuit, and the ENERGYON logic. The ENERGYON logic is used to detect
the presence of valid energy from 100BASE-TX, 10BASE-T, or auto-negotiation signals and is
responsible for driving the ENERGYON signal (bit 1) of the Port x PHY Mode Control/Status Register
(PHY_MODE_CONTROL_STATUS_x).
In this mode, when the ENERGYON signal is cleared, the PHY is powered down and no data is
transmitted from the PHY. When energy is received, via link pulses or packets, the ENERGYON signal
goes high, and the PHY powers up. The PHY automatically resets itself into its previous state prior to
power-down, and asserts the INT7 interrupt (bit 7) of the Port x PHY Interrupt Source Flags Register
(PHY_INTERRUPT_SOURCE_x). The first and possibly second packet to activate ENERGYON may
be lost.
When bit 13 (EDPWRDOWN) of the Port x PHY Mode Control/Status Register
(PHY_MODE_CONTROL_STATUS_x) is low, energy detect power-down is disabled.
7.2.10 PHY Resets
In addition to the chip-level hardware reset (nRST) and Power-On Reset (POR), the PHY supports
three block specific resets. These are discussed in the following sections. For detailed information on
all LAN9313/LAN9313i resets and the reset sequence refer to Section 4.2, "Resets," on page 41.
Note:
The DIGITAL_RST bit in the Reset Control Register (RESET_CTL) does not reset the PHYs.
Only a hardware reset (nRST) or an EEPROM RELOAD command will automatically reload
the configuration strap values into the PHY registers. For all other PHY resets, these values
will need to be manually configured via software.
7.2.10.1
PHY Software Reset via RESET_CTL
The PHY can be reset via the Reset Control Register (RESET_CTL). The Port 1 PHY is reset by
setting bit 1 (PHY1_RST), and the Port 2 PHY is reset by setting bit 2 (PHY2_RST). These bits are
self clearing after approximately 102uS. This reset does not reload the configuration strap values into
the PHY registers.
7.2.10.2
PHY Software Reset via PHY_BASIC_CTRL_x
The PHY can also be reset by setting bit 15 (PHY_RST) of the Port x PHY Basic Control Register
(PHY_BASIC_CONTROL_x). This bit is self clearing and will return to 0 after the reset is complete.
This reset does not reload the configuration strap values into the PHY registers.
7.2.10.3 PHY Power-Down Reset
After the PHY has returned from a power-down state, a reset of the PHY is automatically generated.
The PHY power-down modes do not reload or reset the PHY registers. Refer to Section 7.2.9, "PHY
Power-Down Modes," on page 96 for additional information.
SMSC LAN9313/LAN9313i
97
DATASHEET
Revision 1.2 (04-08-08)