TMS320C6455
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SPRS276M –MAY 2005–REVISED MARCH 2012
7.14.4 Management Data Input/Output (MDIO)
The Management Data Input/Output (MDIO) module implements the 802.3 serial management interface to
interrogate and controls up to 32 Ethernet PHY(s) connected to the device, using a shared two-wire bus.
Application 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.
The EMAC control module is the main interface between the device core processor, the MDIO module,
and the EMAC module. The relationship between these three components is shown in Figure 7-58.
The MDIO uses the same pins for the MII, GMII, and RMII modes. Standalone pins are included for the
RGMII mode due to specific voltage requirements. Only one mode can be used at a time. The mode used
is selected at device reset based on the MACSEL[1:0] configuration pins (for more detailed information,
see Section 3, Device Configuration). Table 7-70 above shows which multiplexed pin are used in the MII,
GMII, and RMII modes on the MDIO.
For more detailed information on the EMAC/MDIO, see the TMS320C645x DSP EMAC/MDIO Module
Reference Guide (literature number SPRU975) .
7.14.4.1 MDIO Device-Specific Information
Clocking Information
The MDIO clock is based on a divide-down of the SYSCLK3 (from the PLL1 controller) and is specified to
run up to 2.5 MHz, although typical operation is 1.0 MHz. Since the peripheral clock frequency is variable,
the application software or driver controls the divide-down amount.
7.14.4.2 MDIO Peripheral Register Descriptions
Table 7-89. MDIO Registers
HEX ADDRESS RANGE ACRONYM REGISTER NAME
02C8 1800 VERSION MDIO Version Register
02C8 1804 CONTROL MDIO Control Register
02C8 1808 ALIVE MDIO PHY Alive Status Register
02C8 180C LINK MDIO PHY Link Status Register
02C8 1810 LINKINTRAW MDIO Link Status Change Interrupt (Unmasked) Register
02C8 1814 LINKINTMASKED MDIO Link Status Change Interrupt (Masked) Register
02C8 1818 - 02C8 181C - Reserved
02C8 1820 USERINTRAW MDIO User Command Complete Interrupt (Unmasked) Register
02C8 1824 USERINTMASKED MDIO User Command Complete Interrupt (Masked) Register
02C8 1828 USERINTMASKSET MDIO User Command Complete Interrupt Mask Set Register
02C8 182C USERINTMASKCLEAR MDIO User Command Complete Interrupt Mask Clear Register
02C8 1830 - 02C8 187C - Reserved
02C8 1880 USERACCESS0 MDIO User Access Register 0
02C8 1884 USERPHYSEL0 MDIO User PHY Select Register 0
02C8 1888 USERACCESS1 MDIO User Access Register 1
02C8 188C USERPHYSEL1 MDIO User PHY Select Register 1
02C8 1890 - 02C8 1FFF - Reserved
Copyright © 2005–2012, Texas Instruments Incorporated C64x+ Peripheral Information and Electrical Specifications 215
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