UM0934 datasheet(103/113 Pages) STMICROELECTRONICS

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UM0934

MAC mode communication example

Doc ID 17389 Rev 2

103/113

MAC mode communication example

This section provides an example which describes how to properly configure two ST7570

modems in MAC mode as Client and Server, respectively, and perform a communication

with a suitable address and credits through the following steps, to be followed after the

initialization and basic configuration steps described in Section 8:

Address configuration (optional)

Server time-outs configuration (optional)

Transmitting a MAC frame from Client to Server

Transmitting a MAC frame from Server to Client.

It is assumed that both station1 and station2 have identical MIB object 00A1h (PLC

configuration) with the exception of operating mode parameter:

●

Access layer mode: MAC mode

●

Operating mode: Client for station1, Server for station2

●

Baud rate: 2400 bps

●

Mains frequency: 50 Hz

●

f0=74 kHz, f1=63.3 kHz

●

Target output gain = -15 dB

●

Tx current control: enabled.

10.1

Step 1: address configuration

Addresses can be configured by accessing MIB object 0001h (local MAC address and the

initiator MAC address) through command CMD_WriteDBRequest().

The time diagram of the commands exchanged between the ST7570 and its external host is

the same as Figure 28, as a CMD_WriteDBRequest() is still involved.

10.1.1

Station1 (Client)

For a Client station (also called initiator), the local MAC address is usually within the FIMA

range (C00h as default value) and LIMA (DFFh as default value), while the initiator MAC

address has no meaning.

In this example:

●

local MAC address = C00h

●

initiator MAC address = 000h (NO-BODY).

For station1 the CMD_WriteDBRequest is composed as:

STX Length

Command

Co de

DATA

CHK

MIB Index

Init MAC Add

Local MAC Add

00.0Ch

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