AMIS-30585 Datasheet, PDF (2/17 Pages) AMI SEMICONDUCTOR – S-FSK PLC Modem

AMIS−30585
ORDERING INFORMATION
Product Name
AMIS30585AGA
Ordering Code (Tubes)
0C585−002−XTD
Package
PLCC 28 452 G
Temperature Range
−25°C to 70°C
Figure 1. S−FSK Modem AMIS−30585 Block Diagram
Description
The AMIS−30585 is a single chip modem dedicated to
power line carrier (PLC) communication in compliance to
the European standard IEC 1334−5−1 and IEC 1334−4−32.
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−30585 are in the range of 9−95 kHz with a typical
separation of 10 kHz.
The circuit is mostly digital. The conversion of the analog
signal is performed at the front−end of the circuit. The
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 micro−processor 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. For the back−end side, the link to the
application hardware, a SCI is provided. The SCI is an easy
to use serial interface, which allows communication
between an external processor used for the application
software and the AMIS−30585 modem. The SCI works on
two wires: TXD and RXD. Baud rate is programmed by
setting 2 bits (BR0, BR1).
Due to the handling of the low protocol layers in the
circuit, the AMIS−30585 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−30585 allows faster development of applications.
The user just needs to send the raw data to the AMIS−30585
and no longer has to take care of the protocol detail of the
transmission over the specific medium. This last part
represents usually 50 percent of the software development
costs.
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