I/O Stream VUART#

IO Stream VUART.

Overview#

Virtual UART (VUART) is a special interface where RTT is used as input channel and the Serial Wire Output(SWO) is used as output channel.

On the receive side, a RTT buffer with a dedicated name is allocated for the reception.

IOStream-VUART uses SWO-stimulus 8 as output channel. Note that the transmit channel also implements a small protocol, so the data is encapsulated in a frame which must be decoded on the host side.

Initialization#

The stream sets itself as the default stream at the end of the initialization function.You must reconfigure the default interface if you have multiple streams in your project else the last stream initialized will be set as the system default stream.

Power manager integration#

Because RTT communication uses the J-link debug interface, when going into EM2 or EM3, the system will actually go into a special EM2 where the high-Frequency clocks are still running and some CPU core functionalities are still powered to maintain the debug features.Therefore it is unwise to keep a debug interface with RTT channel open if you want to test your power consumption.

Communication channel connection#

For connecting to the vuart console you need to use the WSTK and you must be connected using the ethernet link. Then you can open a telnet session on port 4900 using the WSTK IP address. Note that the WSTK firmware decodes the received frame and it outputs only the payload into vuart console.