UM0932 datasheet(9/43 Pages) STMICROELECTRONICS

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UM0932

Functional overview

2.2

ST7580 Power line frames: structure

The ST7580 device can be configured by the external host to transmit and receive frames

over the power line in accordance with three different frames structures:

Physical (PHY) frames, built with some differences between PSK and FSK modulations

(see [·]), as represented in Figure 2:

Figure 2. Physical frame structure

Table 2 lists the fields of PHY frame.

Data Link (DL) frames, adding CRC field to physical SDU.

Figure 3 shows the frame structure:

Figure 3. Data link frame structure

The external host is allowed to choose the CRC algorithm used (length, endianness, fields

involved in calculation) through a dedicated MIB object (modem configuration 00h,

Section 4.2.1).

The length field is automatically handled by ST7580 and its value is by default equal to the

length of payload and CRC fields.

Table 2. PHY frame description

Field name

Length

Description and values

Length

Payload length. Allowable values: from 0 up to 255

Payload

Length

Data bytes

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