Figure 20-13. Interface to Ethernet Jack
T
iva
Cortex-M4
Micr
ocontr
oller
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
49.9Ω
1%
49.9Ω
1%
0.1
m
F
3.3V
49.9Ω
1%
49.9Ω
1%
0.1
m
F
3.3V
3.3V
3.3V
0.1
m
F
0.1
m
F
4.87kΩ
1%
EN0TXOP
EN0TXON
EN0RXIP
EN0RXIN
RBIAS
1
2
3
4
5
6
7
8
75Ω
75Ω
75Ω
75Ω
1000pF
2000V
4700pF
2000V
1MΩ
HX1188FNL
SLVU2.8-4
RJ45 – NoMag
NOTE:
The 0.1
m
F capacitors on pins 2 and 7 of the HX1188FNL
should be located near the physical pins of the transformer.
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 Figure 20-13 on page 1464 must be switched off.
20.5
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 Initialization for the DMA for the Ethernet MAC is as follows:
1.
Write to the Ethernet
MAC DMA Bus Mode (EMACDMABUSMOD)
register to set Host bus
parameters.
2.
Write to the Ethernet
MAC DMA Interrupt Mask Register (EMACDMAIM)
register to mask
unnecessary interrupt causes.
3.
Create the transmit and receive descriptor lists and then write to the
Ethernet MAC Receive
Descriptor List Address (EMACRXDLADDR
) register and the
Ethernet MAC Transmit
June 18, 2014
1464
Texas Instruments-Production Data
Ethernet Controller