TCD_WRITE2
TCD_WRITE2(sc, DMA_TCDn_ATTR(chnum), reg);
TCD_WRITE2(sc, DMA_TCDn_SOFF(chnum), tcd->soff);
TCD_WRITE2(sc, DMA_TCDn_DOFF(chnum), tcd->doff);
TCD_WRITE2(sc, DMA_TCDn_CITER_ELINKNO(chnum), reg);
TCD_WRITE2(sc, DMA_TCDn_BITER_ELINKNO(chnum), reg);
TCD_WRITE2(sc, DMA_TCDn_CSR(chnum), reg);
TCD_WRITE2(sc, DMA_TCDn_CSR(chnum), reg);