Than find and show for everyone.
The problem, that not every example you find would compile with arduino IDE. Example:
dacc_disable_interrupt(DACC, DACC_IER_ENDTX);
pdc_enable_transfer(PDC_DACC, PERIPH_PTCR_TXTEN);
First line is o'key, but second generate an error message, because for some reason IDE doesn't include PDC support.
In this topic I demonstrate workaround, (but of course it's not missile technology) to get direct access to a few registers:
DACC->DACC_TPR = (uint32_t) Sinewave[0]; // DMA buffer
DACC->DACC_TCR = NWAVE;
DACC->DACC_TNPR = (uint32_t) Sinewave[1]; // next DMA buffer
DACC->DACC_TNCR = NWAVE;
DACC->DACC_PTCR = 0x00000100; //TXTEN - 8, RXTEN - 1.
I also get my DUE 2 weeks ago, and already "impressed" by informativity of the atmel data sheet, where registers TCR and TNPR listed in PDC section, and you have to guess that DACC->DACC_TCR would address to right place!