DMA_WRBIT
DMA->dma_mode = 0x90 | (dir ^ DMA_WRBIT);
DMA->dma_mode = mode ^ DMA_WRBIT;
DMA->dma_mode = DMA_SCREG | (mode & DMA_WRBIT);
st_dmacomm(DMA_WRBIT | DMA_FDC | DMA_SCREG, 1);
write_fdreg(DMA_WRBIT | FDC_CS, F_WRITE|hbit|EBIT|PBIT);