6.12 Virtual COM Port
An asynchronous serial connection to the board controller is provided for application data transfer between a host PC and the target
EFM32. This eliminates the need for an external serial port adapter.
VCOM_ENABLE
PH4 (US4_TX #4)
PH5 (US4_RX #4)
PE1 (GPIO)
VCOM_RX
VCOM_TX
Board
Controller
EFM32
USB
Host
PC
Isolation & Level Shift
PH8 (US4_CTS #4)
PH9 (US4_RTS #4)
VCOM_CTS
VCOM_RTS
Figure 6.12. 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. The UART interface consists of four pins and an enable
signal.
Table 6.1. Virtual COM Port Interface Pins
Signal
Description
VCOM_TX
Transmit data from the EFM32 to the board controller
VCOM_RX
Receive data from the board controller to the EFM32
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 EFM32 when it is ready to receive more data
VCOM_ENABLE Enables the VCOM interface, allowing data to pass through to the board controller.
Note:
The VCOM port is only available when the board controller is powered, which requires the J-Link USB cable to be inserted.
UG287: EFM32 Giant Gecko GG11 Starter Kit User's Guide
Peripherals
silabs.com
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