UM0239 datasheet(39/44 Pages) STMICROELECTRONICS

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UM0239

Communication session examples

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8.3

Communication session with Frame Synchronization

In this example, the board connected to COM1 is the Transmitter while the board connected

to COM3 is the Receiver.

Five messages are transmitted across the Mains and the receiving method includes Frame

Synchronization, so incoming data from ST7540 are supervised by the microcontroller on

EVALCOMMBOARD and only the bits that follow the sequence "0x9B58" ("1001-1011-

0101-1000") are sent to the PC.

Actions to perform on GUI connected with COM3:

Click Rx on toolbar to open the Rx Monitor dialog box.

Set FRAME SYNC to ON.

Write "9B58" in Header textbox and "FFFF" in Mask textbox.

Set Data Bytes to "36"

Click ON.

Actions to perform on GUI connected with COM1:

Click Tx on toolbar to open the Tx Monitor dialog box.

Write the preamble "AAAAAAAA" in the hexadecimal textbox.

Add the header "9B58" in the hexadecimal textbox.

Add the text string "transmission with SW synchronization" (length = 36 bytes) in the

ASCII textbox.

Select Sequence Mode and set Nr. to “5”.

Click ON.

Five messages are transmitted.

Using the Frame Synchronization feature, the user ensures that the transmitted bytes

always arrive synchronized to the PC as shown in Figure 25.

Figure 25.

Communication with Frame Synchronization example

COM 1

COM 3

FRAME Header (0x9B58)

UM0239 Datasheet(PDF) 39 Page - STMicroelectronics