By my knowledge there is no api to generate a break sequence. Yes only way to access PUART is through the api.
I would suggest to use interrupt and reinitialize the PUART.
I have tried waiting for the empty fifo, I have tried using sync. write. The only way to get it to run was to introduce a delay loop. I am no too happy with this solution.
I am not at all sure the interrupt scheme would work, as it would have to issue an interrupt after stop bit has ended. This sounds highly unlikely, as this is not the purpose of tx interrupt - this should happen latest just after the byte has been put into shift register, so about the start bit.
OK, I could also probably use a timer, but then again - since there is no way to set it to a specific timeout value I would have to set the precision timer to very high frequency, and then the overhead would be substantial.
So - I have a working solution, but it is Completely Redundant Anti-Pattern.
Any good solutions?