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Coaxial Transceiver. CY7B8392 Datasheet

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Coaxial Transceiver. CY7B8392 Datasheet






CY7B8392 Transceiver. Datasheet pdf. Equivalent




CY7B8392 Transceiver. Datasheet pdf. Equivalent





Part

CY7B8392

Description

Low Power Ethernet Coaxial Transceiver



Feature


CY7B8392 Low Power Ethernet Coaxial Tran sceiver Application This application no te describes the differences between th e 10BASE5 (Ethernet) and 10BASE2 (Cheap ernet) versions of the IEEE 802.3 stand ard, and provides guidelines for design with the CY7B8392. Data is sent out ov er the network in packets. An Ethernet packet consists of the preamble, destin ation address, sou.
Manufacture

Cypress

Datasheet
Download CY7B8392 Datasheet


Cypress CY7B8392

CY7B8392; rce address, length field, data, and a C yclic Redundancy Check (CRC). Each pack et can be viewed as a sequence of 8-bit bytes, with the least significant bit of each byte being transmitted first. A typical Ethernet packet is shown in Fi gure 3. The preamble contains 8 bytes o f alternating ones and zeros, ending wi th two consecutive ones. The preamble a llows the receivin.


Cypress CY7B8392

g PLS to synchronize its clock with the sender. The two consecutive ones at the end of the preamble signify the start of frame packet and are sometimes refer red to as the Start of Frame Delimiter. The destination address is a 6-byte fi eld that specifies the station(s) to wh ich the packet is being sent. Every sta tion examines this field and determines whether it should.


Cypress CY7B8392

accept the packet. The high-order bit o f the destination address is a zero for ordinary addresses and one for group ( multicast) addresses. Group addresses a llow multiple stations to listen to one address. The source address is a 6 byt e field that contains the unique addres s of the station that is transmitting t he packet. The length field is used to determine how many.

Part

CY7B8392

Description

Low Power Ethernet Coaxial Transceiver



Feature


CY7B8392 Low Power Ethernet Coaxial Tran sceiver Application This application no te describes the differences between th e 10BASE5 (Ethernet) and 10BASE2 (Cheap ernet) versions of the IEEE 802.3 stand ard, and provides guidelines for design with the CY7B8392. Data is sent out ov er the network in packets. An Ethernet packet consists of the preamble, destin ation address, sou.
Manufacture

Cypress

Datasheet
Download CY7B8392 Datasheet




 CY7B8392
CY7B8392 Low Power Ethernet Coaxial
Transceiver Application
This application note describes the differences between the
10BASE5 (Ethernet) and 10BASE2 (Cheapernet) versions of
the IEEE 802.3 standard, and provides guidelines for design
with the CY7B8392.
Introduction
The CY7B8392 is a physical layer device used to transmit
data over a shared coaxial medium. It functions as specified
by the IEEE 802.3 standard.
Figure 1 shows a block diagram of a single network node. The
MAC (Media Access Control) is responsible for framing data
and controlling its transmission and reception on the network.
When transmitting the MAC sends NRZ data to the Physical
Signaling (PLS) Layer. The PLS processes the MAC sublayer
data, setting the signaling rate and translating the NRZ data
to Manchester Encoded Data, and sends it to the transceiver.
Figure 2 displays an example of Manchester encoding. In-
stead of straight binary encoding, each bit period is divided
into two equal intervals. To send a one, the voltage is HIGH
(ground) for the first half of the interval and LOW (–2.0 V by
IEEE 802.3) for the second half of the interval. In the case of
a binary zero the reverse is true, the first half of the bit period
the signal is LOW and HIGH the second half.
Data is sent out over the network in packets. An Ethernet
packet consists of the preamble, destination address, source
address, length field, data, and a Cyclic Redundancy Check
(CRC). Each packet can be viewed as a sequence of 8-bit
bytes, with the least significant bit of each byte being trans-
mitted first. A typical Ethernet packet is shown in Figure 3.
The preamble contains 8 bytes of alternating ones and zeros,
ending with two consecutive ones. The preamble allows the
receiving PLS to synchronize its clock with the sender. The
two consecutive ones at the end of the preamble signify the
start of frame packet and are sometimes referred to as the
Start of Frame Delimiter. The destination address is a 6-byte
field that specifies the station(s) to which the packet is being
sent. Every station examines this field and determines wheth-
er it should accept the packet. The high-order bit of the des-
tination address is a zero for ordinary addresses and one for
group (multicast) addresses. Group addresses allow multiple
stations to listen to one address. The source address is a 6
byte field that contains the unique address of the station that
is transmitting the packet. The length field is used to deter-
mine how many bytes are in the data field. This is necessary
because IEEE 802.3 dictates the data portion of a packet
must be a minimum of 46 bytes. If the data portion of a packet
is less than 46 bytes, it is padded with random bits until it is
the legal size. The length field is used to notify the controller
STATION OR DTE
B
U
S
MAC
SUBLAYER
PHYSICAL
SIGNALING
LAYER
OPTIONAL
AUI
CABLE
(USED IN
10BASE5)
MAU
I
S
O
L CY7B8392
A COAXIAL
T TRANSCEIVER
I INTERFACE
O
N DC–DC
CONVERTER
Figure 1. Block Diagram of Single Network Node
COAXIAL
CABLE
010 01
010 0
NRZ DATA
MANCHESTER ENCODED DATA
Figure 2. Manchester Encoding
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
November 9, 1995
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 CY7B8392
CY7B8392 Low Power Ethernet Coaxial
Transceiver Application
SINGLE PACKET
PREAMBLE DESTINA-
TION
ADDRESS
8 BYTES 6 BYTES
SOURCE
ADDRESS
6 BYTES
LENGTH
2 BYTES
DATA
461500
BYTES
CRC
4 BYTES
PREAMBLE DESTINA-
TION
ADDRESS
8 BYTES 6 BYTES
SOURCE
ADDRESS
6 BYTES
Figure 3. Typical Ethernet Packet
which part of the data field is valid. The data field contains an
integral number of bytes ranging from 46 to 1500. The CRC
field contains code that checks on the integrity of a packet.
10BASE5/10BASE2 Ethernet Network
IEEE 802.3 standard allows for two different versions of coax-
ial data transmission, 10BASE5 and 10BASE2. 10BASE5
(Ethernet) uses thick coaxial cable with transceivers directly
attached to the cable network. Because of the inflexibility of
the thick coaxial cable an AUI drop cable is needed to electri-
cally connect the Ethernet transceiver to the Data Terminal
Equipment (DTE). IEEE standard allows up to 500 meter
lengths of RG8 coaxial cable to be used in 10BASE5 appli-
cations. 10BASE2 (Cheapernet) uses a thin, flexible cable
which can be directly attached to the DTE or a Medium At-
tachment Unit (MAU). A maximum of 185 meters of cable is
allowed when using 10BASE2. Figure 4 and Table 1 show the
differences between Ethernet and Cheapernet (sometimes
referred to as Thinnet).
Table 1. Comparison of 10BASE5 and 10BASE2 Media
10BASE5
Cable type
RG8
Maximum cable length 500 meters
Maximum
network length
2500 meters
Attachments per
segment
100
Attachment
spacing
2.5 meters
Topology
Linear bus
10BASE2
RG58 A/U
185 meters
925 meters
30
0.5 meters
Linear bus
Due to the inflexibility of the thick coaxial cable it is difficult to
bring the cable directly to the DTE. To solve this problem an
AUI drop cable is used in 10BASE5 applications. The AUI
cable consists of four individually shielded twisted pairs with
an overall shield covering these pairs. The twisted pairs have
a characteristic impedance of 78 ±5. The cable can be up
to 50 meters in length. The individual shields should be con-
nected to logic ground while the outer shield should be con-
nected to chassis ground. The signal assignments for the AUI
twisted pairs are shown in Table 2. AUI drop cable is typically
not used in 10BASE2 applications because the thin coaxial
cable is flexible enough to be directly attached to the DTE.
TRANSCEIVER
THICK COAX
RG8
STANDARD T
COAX CONNECTOR
RG58 A/U
AUI DROP
CABLE (UP TO 50
METERS)
DTE
(DATA TERMINAL
EQUIPMENT)
MAU
(MEDIUM ATTACHMENT
UNIT) OR DTE
Figure 4. Ethernet vs. Cheapernet
2
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 CY7B8392
CY7B8392 Low Power Ethernet Coaxial
Transceiver Application
Table 2. AUI Interface Signal Assignments
Pins
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Signal
Control In circuit Shield
Control In circuit A
Data Out circuit A
Data In circuit Shield
Data In circuit A
Voltage Common
No Connect
No Connect
Control in circuit B
Data Out circuit B
Data Out circuit Shield
Data In circuit B
Voltage Plus
Voltage Shield
No Connect
Description
Shield for CD± twisted pair
CD+ signal
TX+ signal
Shield for the RX± twisted pair
RX+ signal
CDsignal
TXsignal
Shield for the TX± twisted pair
RXsignal
Voltage supply from DTE
It is possible, through the use of repeaters, to combine several
networks together. These networks can be a single Physical
layer, i.e., only 10BASE2 or only 10BASE5, or it can by a
combination of many different Ethernet physical layers. The
maximum length of a 10BASE5 network using repeaters is
2500 meters, while the maximum length of a 10BASE2 net-
work with repeaters is 925 meters. Figure 5 shows a com-
WORD
PROCESSOR
TAPE
BACKUP
10BASE5 RG8 CABLE
TT
PLOTTER
PERSONAL
COMPUTER
REPEATER
50 OHM TERMINATOR
TRANSCEIVER/MAU
COAXIAL TCONNECTOR
PRINTER
10BASE2 RG58 A/U
T
PERSONAL
COMPUTER
WORKSTATION
FAX
Figure 5. Combined Ethernet and Cheapernet Network
3
T
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