AN2744 datasheet(40/56 Pages) STMICROELECTRONICS

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Board description

AN2744

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5.6

50-pin connector for communication board

The ST7538Q transceiver requires external digital control to perform communication. This is

done through an ST7 microcontroller which is accommodated on the IBU communication

board (see Section 4).

The communication with the ST7 microcontroller involves several signals, which can be

gathered into 3 groups: digital signals, analog signals and power connections. The signals

for each group are listed in Table 7, Table 8 and Table 9.

Beside the ST7538Q input and output signals, the link to the IBU communication board

includes:

– A 2-bit (B_ID_PLM_1 and B_ID_PLM_0) Board Identification Code, which identifies

the hosted power line transceiver. The "00" HW binary configuration makes the

microcontroller able to recognize the ST7538Q reference design board.

– A VDDF_FORCE signal that forces the microcontroller to refer digital interface levels

to VDDF (VDD) supply voltage provided by the ST7538Q reference design board.

This way both the modem and the microcontroller communicate on the same digital

levels.

Figure 38.

Differential mode disturbances protection

ATOP1

ATOP2

ATOP1

ATOP2

AN2744 Datasheet(PDF) 40 Page - STMicroelectronics