Nuvoton NUC970 series, Technical Reference Manual

Page: 621 / 1251

NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 621 - Revision V1.30
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[16] WRITE
Write Command
The WRITE defines the MII management command is a read or write.
0 = MII management command is a read command.
1 = MII management command is a write command.
[15:13] Reserved Reserved.
[12:8] PHYAD
PHY Address
The PHYAD keeps the address to differentiate which external PHY is the target of the MII
management command.
[7:5] Reserved Reserved.
[4:0] PHYRAD
PHY Register Address
The PHYRAD keeps the address to indicate which register of external PHY is the target
of the MII management command.
MII Management Function Frame Format
In IEEE Std. 802.3 clause 22.2.4, the MII management function is defined. The MII management
function is used for the purpose of controlling the PHY and gathering status from the PHY. The
MII management frame format is shown as follow.
Management Frame Fields
PRE ST OP PHYAD REGAD TA DATA IDLE
READ
1…1
01 10 AAAAA RRRRR Z0 DDDDDDDDDDDDDDDD Z
WRITE
1…1
01 01 AAAAA RRRRR 10 DDDDDDDDDDDDDDDD Z
Figure 5.21-6 MII Management Frame Format
MII Management Function Configure Sequence
Read Write
1. Set appropriate EMACn_MDCCR.
2. Set PHYAD and PHYRAD.
3. Set Write t
o 1‟b0
4. Set bit BUSY (EMACn_MIIDA[17])
to 1‟b1 to send a MII
management frame out.
5. Wait BUSY (EMACn_MIIDA[17])
to become 1‟b0.
6. Read data from EMACn_MIID register.
7. Finish the read command.
1. Write data to EMACn_MIID register
2. Set appropriate EMACn_MDCCR.
3. Set PHYAD and PHYRAD.
4. Set Write to 1‟b1
5. Set bit BUSY (EMACn_MIIDA[17])
to 1‟b1 to send a MII
management frame out.
6. Wait BUSY (EMACn_MIIDA[17])
to become 1‟b0.
7. Finish the write command.
Table 5.21-3 MII Management Function Configure Sequence