AMIS-49587_P2 Datasheet, PDF (33/55 Pages) ON Semiconductor – Power Line Carrier Modem

AMIS--49587
7 DETAILED SOFTWARE DESCRIPTION
Figure 29 depicts a typical PLC network with one master and 2 slaves. Each AMIS--49587 is controlled by an external CPU
over a RS232 interface. See paragraph Serial Communication Interface Physical Layer Description for a description on
hardware signals and timings.
LCC
layer
External CPU
RS232
MAC
layer
Physical
Layer
AMIS49587
AFE
PLC Master or Client
Physical
Layer
MAC
layer
AFE
AMIS49587
PLC Slave or Server
RS232
LCC
layer
External CPU
Physical
Layer
MAC
layer
AFE
AMIS49587
PLC Slave or Server
RS232
LCC
layer
External CPU
Figure 29. Typical PLC Network Architecture
This document describes how the RS232 frames need to be
composed to:
♦ Get status information from the AMIS--49587
♦ Configure the AMIS--49587
♦ Send and Receive network data with the
AMIS--49587
♦ Get performance and data path statistics from
AMIS--49587
7.1 CONFIGURE THE AMIS--49587
The AMIS--49587 can operate in different configurations:
♦ Master or Client configuration: A Master is a client
to the data served by one or many slaves on the
power line. It collects data from and controls the
slave devices.
♦ Slave or Server configuration: A Slave is a server of
the data to the Master.
♦ Spy or Monitor configuration: Spy or Monitor mode
is used to only listen to the data that comes across
the power line. Only the physical layer frame
correctness is checked (preamble and SSD, see
Figure 34 Power Line Data Frame Structure). When
the frame is correct, it is passed to the external
processor.
♦ Not set configuration: No valid configuration
command has been passed to the AMIS--49587 after
reset. No power line communication is possible.
This is the state of the AMIS--49587 after a
hardware reset or after a reset command has been
sent to it.
Each mode has its own configuration parameters and
subset of commands.
7.2 OBTAINING STATUS MESSAGES
Opposite to all other commands over the serial interface,
the status message is retrieved from the AMIS--49587 by a
hardware event only. To get the status message the serial
driver on the external CPU needs to pull the T_REQ HW pin
low, like described in paragraph Serial Communication
Interface Physical Layer Description.
Whenever the external controller sends a command to the
AMIS--49587, the T_REQ HW pin should be pulled low to
get a new status message from the MODEM. Only when the
status message indicates that the buffer is not busy, the
command may be send. The AMIS49587 is the master on
the serial interface and needs to be queried to get access to
the bus.
The format of the status message depends on the active
configuration of the AMIS--49587 (not set, slave, master or
monitor).
Table 35. SERIAL PORT STATUS FRAME LAYOUT
START
Status_Data
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