
SPRS457E
– MARCH 2009 – REVISED JUNE 2011
6.22
Management Data Input/Output (MDIO)
The Management Data Input/Output (MDIO) module continuously polls all 32 MDIO addresses in order to
enumerate all PHY devices in the system.
The Management Data Input/Output (MDIO) module implements the 802.3 serial management interface to
interrogate and control Ethernet PHY(s) using a shared two-wire bus. Host software uses the MDIO
module to configure the auto-negotiation parameters of each PHY attached to the EMAC, retrieve the
negotiation results, and configure required parameters in the EMAC module for correct operation. The
module is designed to allow almost transparent operation of the MDIO interface, with very little
maintenance from the core processor. Only one PHY may be connected at any given time.
For more detailed information on the MDIO peripheral, see the TMS320DM36x DMSoC Ethernet Media
Access Controller User's Guide (literature number
SPRUFI5).6.22.1 MDIO Peripheral Register Description(s)
Table 6-96 lists the MDIO registers, their corresponding acronyms, and the device memory locations
(offsets).
Table 6-96. Management Data Input/Output (MDIO) Registers
Offset
Acronym
Register Description
0h
VERSION
Identification and Version Register
04h
CONTROL
MDIO Control Register
08h
ALIVE
PHY Alive Status register
Ch
LINK
PHY Link Status Register
10h
LINKINTRAW
MDIO Link Status Change Interrupt
(Unmasked) Register
14h
LINKINTMASKED
MDIO Link Status Change Interrupt (Masked)
Register
20h
USERINTRAW
MDIO User Command Complete Interrupt
(Unmasked) Register
24h
USERINTMASKED
MDIO User Command Complete Interrupt
(Masked) Register
28h
USERINTMASKSET
MDIO User Command Complete Interrupt
Mask Set Register
2Ch
USERINTMASKCLEAR
MDIO User Command Complete Interrupt
Mask Clear Register
80h
USERACCESS0
MDIO User Access Register 0
84h
USERPHYSEL0
MDIO User PHY Select Register 0
88h
USERACCESS1
MDIO User Access Register 1
8Ch
USERPHYSEL1
MDIO User PHY Select Register 1
6.22.2 Management Data Input/Output (MDIO) Electrical Data/Timing
DEVICE
NO.
UNIT
MIN
MAX
1
tc(MDCLK)
Cycle time, MDCLK
400
ns
2
tw(MDCLK)
Pulse duration, MDCLK high/low
180
ns
3
tt(MDCLK)
Transition time, MDCLK
5
ns
4
tsu(MDIO-MDCLKH)
Setup time, MDIO data input valid before MDCLK high
10
ns
5
th(MDCLKH-MDIO)
Hold time, MDIO data input valid after MDCLK high
0
ns
Copyright
2009–2011, Texas Instruments Incorporated
Peripheral Information and Electrical Specifications
193