Phy management (mdio), Phy management (mdio) -20 – Altera Triple Speed Ethernet MegaCore Function User Manual
Page 56
• To trigger a hardware reset, assert the
reset
signal.
• To trigger a software reset, set the
SW_RESET
bit in the
command_config
register to 1. The
SW_RESET
bit
is cleared automatically when the software reset ends.
Altera recommends that you perform a software reset and wait for the software reset sequence to complete
before changing the MAC operating speed and mode (full/half duplex). If you want to change the operating
speed or mode without changing other configurations, preserve the
command_config
register before
performing the software reset and restore the register after the changing the MAC operating speed or mode.
Figure 4-8: Software Reset Sequence
Receive Frames
Transmit Frames
Flush FIFO
Clear Statistics
Counters
Yes
Yes
Yes
No
No
No
Yes
No
Yes
No
RX _ENA =0
TX _ENA =0
START
(SW_RESET = 1)
END
(SW_RESET = 0)
Frame
Reception
Completed?
Frame
Transmission
Completed?
MAC with
internal FIFO?
Receive
FIFO empty?
Statistics
Counters
Enabled?
If the
SW_RESET
bit is 1 when the line clocks are not available (for example, cable is disconnected),
the statistics registers may not be cleared. The
read_timeout
register is then set to 1 to indicate that
the statistics registers were not cleared.
Note:
PHY Management (MDIO)
This module implements the standard MDIO specification, IEEE 803.2 standard Clause 22, to access the
PHY device management registers, and supports up to 32 PHY devices.
To access each PHY device, write the PHY address to the MDIO register (
mdio_addr0
/
1
) followed by the
transaction data (MDIO Space 0/1). For faster access, the MAC function allows up to two PHY devices to
be mapped in its register space at any one time. Subsequent transactions to the same PHYs do not require
writing the PHY addresses to the register space thus reducing the transaction overhead. You can access the
MDIO registers via the Avalon-MM interface.
For more information about the registers of a PHY device, refer to the specification provided with the device.
Functional Description
Altera Corporation
UG-01008
PHY Management (MDIO)
4-20
2014.06.30