Texas Instruments TMS320TCI6486 - Manual (Page 87)

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4.12 MDIO User Access Register 0 (USERACCESS0)
The MDIO user access register 0 (USERACCESS0) is shown in Figure 39 and described in Table 32 .
Figure 39. MDIO User Access Register 0 (USERACCESS0)
31 30 29 28 26 25 21 20 16
GO WRITE ACK Reserved REGADR PHYADR
R/WS-0 R/W-0 R/W-0 R-0 R/W-0 R/W-0
15 0
DATA
R/W-0
LEGEND: R = Read only; R/W = Read/Write; R/WS = Read/Write 1 to set; -n = value after reset
Table 32. MDIO User Access Register 0 (USERACCESS0) Field Descriptions
Bit Field Value Description
31 GO Go bit. Writing a 1 to this bit causes the MDIO state machine to perform an MDIO access when it is
convenient for it to do so; this is not an instantaneous process. Writing a 0 to this bit has no effect.
This bit is writeable only if the MDIO state machine is enabled. This bit will self clear when the
requested access has been completed. Any writes to the USERACCESS0 register are blocked
when the GO bit is 1.
30 WRITE Write enable bit. Setting this bit to a 1 causes the MDIO transaction to be a register write, otherwise
it is a register read.
0 The user command is a read operation
1 The user command is a write operation
29 ACK Acknowledge bit. This bit is set if the PHY acknowledged the read transaction.
28-26 Reserved 0 Reserved
25-21 REGADR Register address bits. This field specifies the PHY register to be accessed for this transaction.
20-16 PHYADR PHY address bits. This field specifies the PHY to be accessed for this transaction.
15-0 DATA User data bits. These bits specify the data value read from or to be written to the specified PHY
register.
87 SPRUEF8F – March 2006 – Revised November 2010 C6472/TCI6486 EMAC/MDIO
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