Hi Naven,
Depending on the length of the DMA transmission, and the destination Address for the DMA transfer the ending address can be calculated, and a flag can be manually introduced to determine the end of a given transmission.
There's some code examples included in the LPC4370's LPC-Open package, namely, the DMA timertrig example:
<…lpcopen_3_02_keil_iar_lpclink2_4370\LPC43xx_18xx\prj_link4370\lpcxpresso\periph_dma_timertrig>
Please let me know if you need any more information.
Take care, best regards,
Sebastian