UM1518 datasheet(27/37 Pages) STMICROELECTRONICS

27 / 37 page

UM1518

Services

Doc ID 022791 Rev 2

27/37

Slave node

When a node is set as "Slave" for a Ping session, it automatically answers each received

frame by sending a packet built with identical electrical features and Payload data.

Before starting the Ping session, the node needs to be configured with two frequency values

for reception and the corresponding functional modulations. These values are overwritten to

MIB object 01h (Physical configuration) and the node is set to work on a dual channel

reception.

From a functional point of view, a Slave Address Number is assigned as well, as 1-byte

value. The Slave node re-transmits the frames with Slave Address subfield (Figure 23)

equal to the Slave Address Number assigned to it.

The GUI allows the user to choose between two Stop conditions:

1.Frame number: the GUI stops the Ping session after the node receives a fixed number of

Indication messages (DL_DataIndication and DL_SnifferIndication);

2.Time: the GUI stops the Ping session after a number of seconds selected by the user (if

the number set through the GUI is equal to 0, the Ping session ends when the "Stop Ping"

button is pressed).

After an Indication message, three cases are taken into account and displayed by the GUI:

1. A DL_DataIndication has been notified by the modem and the Frame Address subfield is

equal to the Frame Address parameter set to the node; the Node sends a powerline frame

with same electrical conditions (Frequency carrier, modulation) and data Payload (in

accordance with Figure 23 subfields). The dedicated "Received OK" counter increases.

2. A DL_DataIndication has been notified by the modem and the Frame Address subfield is

not equal to the Frame Address parameter set to the node; the dedicated "RX Wrong

Address" counter increases and any frame is transmitted.

3. A DL_SnifferIndication has been notified by the ST7580: the dedicated "RX Wrong CRC"

counter increases. However, if the Frame Address subfield is equal to the Frame Address

parameter set to the node, a powerline frame is transmitted with same electrical conditions

(Frequency carrier, modulation) and data payload (in accordance with Figure 23 subfields).

Figure 25 reports the flowchart of Master node throughout the Ping session:

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