It seems somewhat odd to me, reading the NS7520 documentation, that the UART receive DMA channel only seems to be closed on a byte match condition or on the expiry of one of the two timers. I would prefer it if a DMA buffer were also closed on either a DSR transition or a receive break condition. The latter I can see as being likely: any receive error should close the buffer with a Premature Complete condition in the DMA channel, I would think. Anybody know if an incoming break does close a DMA buffer?