Texas Instruments RM48 series, Technical Reference Manual

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MDIO Registers
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1474 SPNU503C – March 2018
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EMAC/MDIO Module
28.4.3 PHY Acknowledge Status Register (ALIVE)
The PHY acknowledge status register (ALIVE) is shown in Figure 28-30 and described in Table 28-27 .
Figure 28-30. PHY Acknowledge Status Register (ALIVE)
31 0
ALIVE
R/W1C-0
LEGEND: R/W = Read/Write; W1C = Write 1 to clear (writing a 0 has no effect); - n = value after reset
Table 28-27. PHY Acknowledge Status Register (ALIVE) Field Descriptions
Bit Field Value Description
31-0 ALIVE MDIO Alive bits. Each of the 32 bits of this register is set if the most recent access to the PHY with
address corresponding to the register bit number was acknowledged by the PHY; the bit is reset if the
PHY fails to acknowledge the access. Both the user and polling accesses to a PHY will cause the
corresponding ALIVE bit to be updated. The ALIVE bits are only meant to be used to give an indication of
the presence or not of a PHY with the corresponding address. Writing a 1 to any bit will clear it, writing a 0
has no effect.
0 The PHY fails to acknowledge the access.
1 The most recent access to the PHY with an address corresponding to the register bit number was
acknowledged by the PHY.
28.4.4 PHY Link Status Register (LINK)
The PHY link status register (LINK) is shown in Figure 28-31 and described in Table 28-28 .
Figure 28-31. PHY Link Status Register (LINK)
31 0
LINK
R-0
LEGEND: R = Read only; - n = value after reset
Table 28-28. PHY Link Status Register (LINK) Field Descriptions
Bit Field Value Description
31-0 LINK MDIO Link state bits. This register is updated after a read of the generic status register of a PHY. The bit
is set if the PHY with the corresponding address has link and the PHY acknowledges the read
transaction. The bit is reset if the PHY indicates it does not have link or fails to acknowledge the read
transaction. Writes to the register have no effect.
0 The PHY indicates it does not have a link or fails to acknowledge the read transaction.
1 The PHY with the corresponding address has a link and the PHY acknowledges the read transaction.