Handle a DMA status exception
void z8530_dma_status (
|struct z8530_channel * chan|
struct z8530_channel * chan
Z8530 channel to process
A status event occurred on the Z8530. We receive these for two reasons
when in DMA mode. Firstly if we finished a packet transfer we get one
and kick the next packet out. Secondly we may see a DCD change.