AMIS-49587 Datasheet, PDF (11/59 Pages) ON Semiconductor – Power Line Carrier Modem

AMIS−49587
INTRODUCTION
GENERAL DESCRIPTION
The AMIS−49587 is a single chip half duplex S−FSK
modem dedicated to power line carrier (PLC) data
transmission on low− or medium−voltage power lines. The
device offers complete handling of the protocol layers from
the physical up to the MAC. AMIS−49587 complies with the
EN 50065 CENELEC and the IEC 1334−5−1 standards. It
operates from a single 3.3 V power supply and is interfaced
to the power line by an external power driver and
transformer. An internal PLL is locked to the mains
frequency (50 Hz or 60 Hz) and is used to synchronize the
data transmission at data rates of 300, 600, 1200 and
2400 baud for a 50 Hz mains frequency, corresponding to 3,
6, 12 or 24 data bits per half cycle of the mains frequency
(50 Hz or 60 Hz).
S−FSK is a modulation and demodulation technique that
combines some of the advantages of a classical spread
spectrum system (e.g. immunity against narrow band
interferers) with the advantages of the classical FSK system
(low complexity). The transmitter assigns the space
frequency fS to “data 0” and the mark frequency fM to “data
1”. The difference between S−FSK and the classical FSK
lies in the fact that fS and fM are now placed far from each
other, making their transmission quality independent from
each other (the strengths of the small interferences and the
signal attenuation are both independent at the two
frequencies). The frequency pairs supported by the
AMIS−49587 are in the range of 9−95 kHz with a typical
separation of 10 kHz.
The conditioning and conversion of the signal is
performed at the analog front−end of the circuit. The further
processing of the signal and the handling of the protocol is
digital. At the back−end side, the interface to the application
is done through a serial interface. The digital processing of
the signal is partitioned between hardwired blocks and a
microprocessor block. The microprocessor is controlled by
firmware. Where timing is most critical, the functions are
implemented with dedicated hardware. For the functions
where the timing is less critical, typically the higher level
functions, the circuit makes use of the ARM 7TDMI
microprocessor core.
The processor runs DSP algorithms and, at the same time,
handles the communication protocol. The communication
protocol, in this application, contains the MAC = Medium
Access Control Layer. The program running on the
microprocessor is stored into an on−board ROM. The
working data necessary for the processing is stored in an
internal RAM. At the back−end side the link to the
application hardware is provided by a SCI. The SCI is an
easy to use serial interface, which allows communication
between an external processor used for the application
software and the AMIS−49587 modem. The SCI works on
two wires: TXD and RXD. Baud rate is programmed by
setting 2 bits (BR0, BR1).
Because the low protocol layers are handled in the circuit,
the AMIS−49587 provides an innovative architectural split.
Thanks to this, the user has the benefit of a higher level
interface of the link to the PLC medium. Compared to an
interface at the physical level, the AMIS−49587 allows
faster development of applications. The user just needs to
send the raw data to the AMIS−49587 and no longer has to
take care of the protocol detail of the transmission over the
specific medium. This last part represents usually 50% of the
software development costs.
CLIENT
Application
AMIS−49587 in
MASTER mode
SERVER
Application
AMIS−49587 in
SLAVE mode
SERVER
Application
AMIS−49587 in
SLAVE mode
SPY
Application
AMIS−49587 in
MONITOR mode
TEST
Application
AMIS−49587 in
TEST mode
Major User Type
Minor User Type
Figure 3. Application Examples
AMIS−49587 is an integrated circuit intended to connect
equipment using Distribution Line Carrier (DLC)
communication. It serves two major and two minor types of
applications:
• Major type:
♦ Server Applications which provide resources to a
client. A typical application is an electricity meter
device equipped for DLC
♦ Client Applications which exploit remote servers. A
typical application is a concentrator system is a
• Minor type:
♦ Spy Applications, used to monitor or test DLC
communication on the channel.
♦ Test Mode, used to test the compliance of a PLC
modem conforms to CENELEC. (Continuous
broadcast of f_S or f_M).
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