UM1817 datasheet(19/58 Pages) STMICROELECTRONICS

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UM1817

Hardware layout and configuration

The RS-485 communication is supported by the RS-485 transceiver ST3485EBDR which is

connected to pin 4 and pin 9 of D-type 9-pins connectors CN9 (share same connector with

USART1), see Table 11.

2.9

Touch sensing buttons

Two touch sensing buttons are supported on the STM32091C-EVAL evaluation board and

they are connected to three capacitive sensing channels (PD[12:14]) in group8 with active

shield being connected to two capacitive sensing channels (PB11 and PB12) in group6 (see

Table 12).

Table 10. RS-232 and IrDA related jumpers

Jumper

Description

JP13

RS232_RX is connected to RS-232 transceiver and RS-232 communication is

enabled when JP13 is set as shown to the right (Default setting):

RS485_RX is connected to RS-485 transceiver and RS-485 communication is

enabled when JP13 is set as shown to the right:

IrDA_RX is connected to IrDA transceiver and IrDA communication is enabled when

JP13 is set as shown to the right:

Table 11. RS-485 related solder bridges

Jumper

Description

SB15, SB18

The external failsafe biasing are enabled when solder bridges SB15 and SB18 are

closed

Default Setting: Not fitted

SB19

The bus termination is enabled when solder bridge SB19 is closed.

Default Setting: Not fitted

SB16

The AC termination is disabled when solder bridge SB16 is closed for high baud rate

communication.

Default Setting: Not fitted

UM1817 Datasheet(PDF) 19 Page - STMicroelectronics