Mac phy maintenance register – Rainbow Electronics AT75C220 User Manual
Page 47
AT75C220
47
MAC PHY Maintenance Register
Register Name: ETH_MAN
Access Type: Read/write
Reset Value: 0x0
Writing to this register starts the shift register that controls the serial connection to the PHY. On each shift cycle the MDIO
pin becomes equal to the MSB of the shift register and LSB of the shift register becomes equal to the value of the MDIO
pin. When the shifting is complete an interrupt is generated and the IDLE field is set in the Network Status register.
When read will give current shifted value.
•
DATA
For a write operation this is written with the data to be written to the PHY. After a read operation this contains the data
read from the PHY.
•
CODE
Must be written to 10. Will read as written.
•
REGA
Register address. Specifies the register in the PHY to access.
•
PHYA
PHY address. Normally will be 0.
•
RW
Read/write Operation. 10 is read. 01 is write. Any other value is an invalid PHY management frame.
•
HIGH
Must be written with 1 to make a valid PHY management frame.
•
LOW
Must be written with 0 to make a valid PHY management frame.
31
30
29
28
27
26
25
24
LOW
HIGH
RW
PHYA
23
22
21
20
19
18
17
16
PHYA
REGA
CODE
15
14
13
12
11
10
9
8
DATA
7
6
5
4
3
2
1
0
DATA