Even though, according to the reference manual, swm should be enabled per default, it needs to be reenabled in the [usart example](https://github.com/lpc-rs/lpc8xx-hal/blob/8ca1a9ce19eef65904695a24bb6113420578966d/examples/usart.rs#L20) for the lpc845. It's listed as disabled per default in the svd. It shouldn't be possible to use it in a disabled state