ETC LXT901/LXT907

Design Guide for LXT901/907
Ethernet Interface Connection to
Motorola MC68EN360 Controller
Application Note
January 2001
Order Number: 249142-001
As of January 15, 2001, this document replaces the Level One document known as AN035.
Information in this document is provided in connection with Intel® products. No license, express or implied, by estoppel or otherwise, to any intellectual
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intended for use in medical, life saving, or life sustaining applications.
Intel may make changes to specifications and product descriptions at any time, without notice.
Designers must not rely on the absence or characteristics of any features or instructions marked “reserved” or “undefined.” Intel reserves these for
future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them.
The LXT901/907 Ethernet Interface may contain design defects or errors known as errata which may cause the product to deviate from published
specifications. Current characterized errata are available on request.
Contact your local Intel sales office or your distributor to obtain the latest specifications and before placing your product order.
Copies of documents which have an ordering number and are referenced in this document, or other Intel literature may be obtained by calling
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Copyright © Intel Corporation, 2001
*Third-party brands and names are the property of their respective owners.
Application Note
Design Guide for LXT901/907 Ethernet Interface
Contents
1.0
General Description .................................................................................................. 5
1.1
1.2
2.0
Features ................................................................................................................ 5
Applications ........................................................................................................... 5
LXT90x / QUICC Interface ....................................................................................... 7
2.1
2.2
2.3
Setting QUICC Parameters ................................................................................... 7
External Components............................................................................................ 8
2.2.1 Magnetics .................................................................................................8
Layout Guidelines.................................................................................................. 9
1
2
Typical LXT901/LXT907 Device and MC68EN360 QUICC Connection ............... 6
Typical Full-Duplex 10BASE-T Connection........................................................... 9
1
Pin Connections .................................................................................................... 7
Figures
Tables
Application Note
3
Design Guide for LXT901/907 Ethernet Interface
4
Application Note
Design Guide for LXT901/907 Ethernet Interface
1.0
General Description
This application note describes a method for connecting the LXT901 or LXT907 Ethernet Interface
Adapter to the Motorola MC68EN360 Quad Integrated Communications Controller (QUICC) with
Ethernet capability. The QUICC/LXT901 combination makes designing routers, bridges, print
servers and other, similar products simple and fast.
The LXT901 and LXT907 devices have advanced features that make design and fabrication faster
and cheaper than typical competitors’ products. These two devices meet all of the Motorola
QUICC design requirements with minimal external circuitry needed to use the MC68EN360
features. Either of these devices gives the lowest cost, highest performance possible with the
Motorola QUICC.
1.1
Features
• Glueless interface to the MC68EN360 QUICC controller in 10 Mbps Ethernet/IEEE 802.3
LAN with either twisted- pair connection or AUI transceiver
•
•
•
•
1.2
Integrated filters make design faster, fabrication cheaper
Integrated LED drivers for operation monitoring
Supports full duplex operation
Automatic port selection makes choosing between the twisted-pair and AUI options seamless
Applications
This application note addresses the Ethernet LAN side of the circuit only. Intel also offers a
complete line of T1/E1 and XDSL transceivers for WAN connections.
Application Note
5
Design Guide for LXT901/907 Ethernet Interface
Figure 1. Typical LXT901/LXT907 Device and MC68EN360 QUICC Connection
SCCI
PROGRAMMIG
OPTIONS
CLK[1:4]
CLK[1:4]
TxD
RxD
RTS
CD
CTS
Parallel I/O
LINE STATUS
330
330
CLKI
RCLK
TCLK
TXD
RXD
TEN
CD
COL
LBK
PAUL
AUTOSEL
NTH
STP/DSQE
LI
MD0
MD1
RJAB
RLD
RCMPT
JAB
PLR
REMOTE
STATUS
330
330
Green Red Red
Red
20 MHz
LEDL
RJ45
1 1 : 1 16
TPIN
W
50 W
6
50
TPIP
TPONB
TPONA
LEDC/FDE
LEDR
LEDT/PDN
0.1 µF
20 pF
CLKO
LXT901 or LXT907
20 pF
MC68EN360
75 W
1%
W
1%W
1%
3
14
NOTE:
LXT901/907 pin-out
varies with IC package
design. See Table 1.
5
4
6
1: 2
11
37.5
3
To 10 BASE-T
TWISTED-PAIR
NETWORK
2
37.5
TPOPA
TPOPB
8
W
1%
78
W1
1
D - CONNECTOR
to AUI DROP
CABLE
75
CIN
9
16
1
9
2
10
CIP
78
DON
2
15
W4
13
3
11
4
12
5
0.1 µF
DOP
78
DIN
5
12
W7
10
TEST
13
6
14
7
15
8
DIP
+5 V
8
9
W
1%
Fuse
12.4 k
VCC1
RBIAS
+ 12 V
VCC2
GND1 GND2
Chassis
Gnd
0.1 µF
6
Application Note
Design Guide for LXT901/907 Ethernet Interface
2.0
LXT90x / QUICC Interface
The LXT901 is available in either a 44-pin PLCC or a 64-pin TQFP package. The LXT907 is
available in a 44-pin PLCC package. The PLCC package is pin compatible for both devices except
for pin 37. This pin is STP (unshielded/shielded twisted-pair select) on the LXT901 and DSQE
(Disable SQE) on the LXT907 device.
The following pins on the LXT901 or LXT907 device connect to the MC68EN360 SCC1 signals
as shown in Table 1.
Table 1.
Pin Connections
LXT901/LXT907 Device
PLCC
Pin
TQFP
Pin
Signal
Motorola QUICC
MC68EN360
SCC1 Signal
28
47
RCLK
CLK1-41
11
23
TCLK
CLK1-41
12
24
TXD
TXD
26
45
RXD
RXD
13
25
TEN
RTS2
27
46
CD
CD2
16
28
COL
CTS2
22
38
LBK
40
3
PAUI
17
29
AUTOSEL
4
13
NTH
37 (901)
59
STP
37 (907)
n/a
DSQE
Connect these bits to
the Parallel I/O bus on
the QUICC3 and
program as needed.
1. The design must provide separate clocks for TCLK and
RCLK. Any of the clocks on the QUICC will do.
2. These signals are active high in this application.
3. Please check the Motorola specification for the connections
needed for the desired result.
2.1
Setting QUICC Parameters
Refer to the Motorola MC68360 Quad Integrated Communications Controller User’s Manual for
the QUICC function settings. The following considerations should be reviewed for an optimized
design:
• Bypass both the Digital Phase-Locked Loop (DPLL) and Manchester Encoding/Decoding
function for Ethernet operation.
• The TCI (Time Clock Invert) bit must be High to allow the QUICC to clock the data out to the
LXT901 or LXT907 device on the rising edge of the clock pulse. This improves data setup
time at the 10 Mbps speed used by Ethernet. TCI is bit 28 of the General SCC Mode Register
(GSMR).
Application Note
7
Design Guide for LXT901/907 Ethernet Interface
• The MODE bits (0:3) must be set to 1, 1, 0, 0 respectively. The Transparent Receiver (TRX)
and Transparent Transmitter bits (TTX), bits 43 and 44, must both be 0 (normal operation) or 1
(transparent operation). Do not mix TRX and TTX values. The 0 setting is recommended; in
transparent mode, the QUICC does not manipulate protocols in the data stream.
• The Transmit FIFO Length (TFL) bit should be 0. TFL is bit 38 in the GSMR. The Receive
FIFO Width (RFW) bit, bit 37, should also be 0.
• GSMR bits 19 and 20 are the Transmit Preamble Pattern (TPP) bits. For Ethernet operation,
set them to 0, 1 to transmit a repeating 10 pattern as a preamble.
• Figure 2 shows a typical set up for a full-duplex 10BASE-T LAN connection, using the
LXT907 device. This application requires only the TP transformer, two 18 pF capacitors, two
330 Ω resistors, two 24.9 Ω 1% resistors, one 12.4 kΩ 1% resistor, and a green LED. The 20
MHz clock signal is common in all 10BASE-T applications, so no crystal is required. All
QUICC parameters remain the same.
• This completes the Ethernet/IEEE 802.3 LAN side of the circuit setup. There are other steps
in designing a working circuit that go beyond the scope of this application note.
2.2
External Components
The application on page 1 requires two DIP transformer packages for isolation and impedance
matching on the AUI or twisted-pair transmit and receive lines. Additional components for the
connection include:
•
•
•
•
•
•
•
•
•
•
•
2.2.1
20 MHz crystal (one each, or external 20 MHz clock)
300 Ω, 1% resistor (four each)
50 Ω, 1% resistor (two each)
75 Ω, 1% resistor (two each)
78 Ω, 1% resistor (three each)
37.5 Ω, 1% resistor (two each)
12.4 kΩ, 1% resistor (one each)
0.1 µF capacitor (three each)
20 pF capacitor (two each, required with Xtal only)
Red LED (three each, optional)
Green LED (one each, optional)
Magnetics
Refer to Application Note 73, Magnetic Manufacturers for Networking Product Applications, for a
list of magnetic manufacturers and part numbers. The latest version is located on the Intel web site,
developer.intel.com/design/network/. This listing constitutes a reference only, and is not a
recommendation. It is the responsibility of the system designer to ensure that all components, both
individually and collectively, are suitable for the intended application.
8
Application Note
Design Guide for LXT901/907 Ethernet Interface
2.3
Layout Guidelines
Fabricate the circuit as shown in the diagram on page 1. Isolate the bias circuit at RBIAS and locate
the resistor as close as possible to the pin. If this resistor is not positioned properly it may act as an
antenna and cause erratic performance. Keep it away from other components or signal traces, and
do not run any signals under the resistor. Be sure to use a bypass capacitor at each Vcc pin.
Figure 2. Typical Full-Duplex 10BASE-T Connection
20 MHz
CLK[1:4]
CLK[1:4]
RCLK
TCLK
TXD
RXD
TEN
CD
COL
LBK
DSQE
TxD
RxD
SCCI
RTS
CD
CTS
CLKI
RJ45
CLKO
1
TPIN
TPIP
TPONA
6
330 Ω
NTH
1: 2
11
24.9 Ω 1%
4
3
2
24.9 Ω 1%
LXT907
+5 V
PAUL
AUTOSEL
MD0
MD1
14
3
TPOPA
6
5
TPONB
LEDC/FDE
+5 V
16
100 Ω
Parallel I/O
330 Ω
1:1
8
9
To 10 BASE-T TWISTEDPAIR NETWORK
MC68EN360
1
TPOPB
Green
LEDL
12.4 kΩ 1%
LI
+5 V
RBIAS
VCC1
VCC2
GND1
GND2
0.1 µF
Application Note
9
Design Guide for LXT901/907 Ethernet Interface
10
Application Note