MSP4
3
2
E4
Mi
cro
co
n
tro
lle
r
1
2
3
6
7
8
16
15
14
11
10
9
1
2
3
4
5
6
7
8
9
10
TX+
TX-
RX+
TERM1A
TERM1B
RX-
TERM2A
TERM2B
CHASIS
CHASIS
49.9
1%
49.9
1%
0.1 mF
3.3 V
49.9
1%
49.9
1%
0.1mF
3.3 V
3.3 V
3.3 V
0.1 mF
0.1 mF
4.87 k
1%
EN0TXOP
EN0TXON
EN0RXIP
EN0RXIN
RBIAS
1
2
3
4
5
6
7
8
75
75
75
75
1000 pF
2000 V
4700 pF
2000 V
1M
HX1188FNL
SLVU2.8-4
RJ45
±
NoMag
Ethernet PHY
935
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
Ethernet Controller
•
MIIW: Write/Read Initiation. This bit is programmed to a 0 to indicate that a read operation is to be
executed.
•
MIIB: MII Busy. This bit is set to 1 to indicate that the MII is now busy with a read operation. The
EMAC clears this bit when the write has been transmitted.
3. Wait for the write to complete by polling the MIIB bit.
4. When the MIIB is clear, read the contents of the EMACMIIDATA register.
15.4.3 Interface Configuration
shows the proper method for interfacing the Ethernet Controller to a 10/100BASE-T Ethernet
jack.
Figure 15-15. Interface to Ethernet Jack
The Ethernet PHY is designed to work with transformers that meet the IEEE 802.3 standard. To utilize the
Auto-MDIX (AMDIX) capability of the Ethernet PHY, a symmetrical transformer is recommended. The
Pulse HX1188 transformer has been tested and is known to successfully interface to the Ethernet PHY.
NOTE:
If the PHY is not to be used, then the EN0RXIN / EN0TX0N EN0RXIP / EN0TX0P pair
should be left unconnected and the RBIAS pin should be unconnected as well.
NOTE:
When entering hibernation in VDD3ON mode, the supply rails to the Ethernet resistors R1,
R2, R3, R4 found in
must be switched off.
15.5 Initialization and Configuration
The MAC module and registers are enabled and powered at reset. When reset has completed, the
application should enable the clock to the Ethernet MAC by setting the R0 bit in the Ethernet Controller
Run Mode Clock Gating Control (RCGCEMAC) register at System Control Module offset 0x69C. When the
PREMAC register, at System Control offset 0xA9C reads as 0x0000.0001, the EMAC registers are ready
to be accessed.
The EMAC interface defaults to MII mode. If RMII mode is required, follow these steps:
1. Enable the external clock source input to the RMII interface signal EN0RREF_CLK by setting both the
ECEXT and CLKEN bit in the in the Ethernet Clock Configuration (EMACCC) register at offset 0xFC8.