EMAC Registers
951
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Ethernet Controller
15.6.5 EMACMIIADDR Register (Offset = 0x10) [reset = 0x0]
Ethernet MAC MII Address (EMACMIIADDR)
The Ethernet MAC MII address (EMACMIIADDR) register controls the management cycles to the PHY
through the management interface.
EMACMIIADDR is shown in
and described in
Return to
Figure 15-20. EMACMIIADDR Register
31
30
29
28
27
26
25
24
RESERVED
R-0x0
23
22
21
20
19
18
17
16
RESERVED
R-0x0
15
14
13
12
11
10
9
8
PLA
MII
R/W-0x0
R/W-0x0
7
6
5
4
3
2
1
0
MII
CR
MIIW
MIIB
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
Table 15-29. EMACMIIADDR Register Field Descriptions
Bit
Field
Type
Reset
Description
31-16
RESERVED
R
0x0
15-11
PLA
R/W
0x0
Physical Layer Address. This field gives the PHY address of the MII
module. Values 1- 31 (0x1 to 0x1F) are available for external PHY
addresses. The integrated PHY's address is 0x00. To access the
integrated PHY registers, the PLA bits[15:11] must be zeros.
10-6
MII
R/W
0x0
MII Register. These bits select the desired MII registers in the
selected PHY device.
5-2
CR
R/W
0x0
Clock Reference Frequency Selection. The clock that is sent to the
MAC Clock and Status (CSR) registers is the gated System Clock
(SYSCLK). The SYSCLK is divided down through the CR field to
produce an MDC clock that is between approximately 1.0 MHz and
2.5 MHz. The application must program the appropriate CR field
based on the System Clock input. 0x4-0xF = Reserved
0x0 = The frequency of the System Clock is 60 to 100 MHz providing
a MDIO clock of SYSCLK/42.
0x1 = The frequency of the System Clock is 100 to 150 MHz
providing a MDIO clock of SYSCLK/62.
0x2 = The frequency of the System Clock is 20 to 35 MHz providing
a MDIO clock of System Clock/16.
0x3 = The frequency of the System Clock is 35 to 60 MHz providing
a MDIO clock of System Clock/26.
1
MIIW
R/W
0x0
MII Write.
0x0 = Read operation is active and read data is placed in the MII
Data register (EMACMIIDATA).
0x1 = PHY is notified that this is a write operation using the MII Data
Register (EMACMIIDATA).