UM0239 datasheet(13/44 Pages) STMICROELECTRONICS

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UM0239

Getting started

13/44

Getting started

4.1

Selecting the COM port

The first step required for using the PLM Demo Kit program is to select the correct COM port

for communication between the PC and the ST7538/40 PLM Demo Board and the ST7 MCU

EVALCOMMBOARD.

Warning:

When running the program for the first time, the user must

perform a Control Register Writing operation before being

able to access the other GUI sections.

This action is mandatory because the only communication

interface available from the MCU on EVALCOMMBOARD to

ST7540 is synchronous, while the default Mains interface of

ST7540 is asynchronous. The only action that can be

performed before a Control Register Writing is a Control

always synchronous.

Figure 4.

COM selection

Once the correct COM port is selected, the program starts communication with the

EVALCOMMBOARD and automatically recognizes the type of device (ST7538 or ST7540)

on the PLM Board and the firmware revision of the ST7 microcontroller (on

EVALCOMMBOARD). The status bar also displays this data as shown in Figure 3.

If a communication problem occurs during COM selection, e.g. if the Demo Board has not

been properly connected to PC, a message box appears and the user must select the

device to manage (see Figure 5). The user must select the ST7540 device to ensure correct

program behavior (see Note 1).

It is possible to control a maximum of four devices (from COM1 to COM4) using a single

Personal Computer by launching four instances of the program. In order to identify the

instances, a different window background color is used for every COM port. After the COM

selection, the user can access all GUI sections.

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