5.6 Virtual COM Port

An asynchronous serial connection to the board controller is provided for application data transfer between a host PC and the target

EFR32. This eliminates the need for an external serial port adapter.

VCOM_ENABLE

PA0 (US0_TX#0)

PA1 (US0_RX#0)

PA5 (GPIO)

VCOM_RX

VCOM_TX

Board

Controller

EFR32

USB

Host

PC

Isolation & Level Shift

PA2 (US0_CTS#30)

PA3 (US0_RTS#30)

VCOM_CTS

VCOM_RTS

ETH

or

Figure 5.6. Virtual COM Port Interface

The Virtual COM port consists of a physical UART between the target device and the board controller, and a logical function in the

board controller that makes the serial port available to the host PC over USB or Ethernet. The UART interface consists of four pins and

an enable signal.

Table 5.1. Virtual COM Port Interface Pins

Signal

Description

VCOM_TX

Transmit data from the EFR32 to the board controller

VCOM_RX

Receive data from the board controller to the EFR32

VCOM_CTS

Clear to Send hardware flow control input, asserted by the board controller when it is ready to receive more data

VCOM_RTS

Request to Send hardware flow control output, asserted by the EFR32 when it is ready to receive more data

VCOM_ENABLE Enables the VCOM interface, allowing data to pass through to the board controller.

The parameters of the serial port, such as baud rate or flow control, can be configured using the admin console. The default settings

depends on which radio board is used with the Wireless STK Mainboard.

Note: The VCOM port is only available when the board controller is powered, which requires the J-Link USB cable to be inserted.

UG261: EFR32MG12 2.4 GHz 10 dBm Radio Board User's Guide

Peripherals

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