3.1.2.3 Limitations

Not all UART features are implemented in the on-board debugger CDC. The constraints are outlined here:

Baud rate: Must be in the range of 1200 bps to 500 kbps. Any baud rate outside this range will be set to the closest limit, without warning. Baud rate can be changed on-the-fly.
Character format: Only 8-bit characters are supported.
Parity: Can be odd, even, or none.
Hardware flow control: Not supported.
Stop bits: One or two bits are supported.

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