よくある質問(FAQ)
What is the difference between the DREQ/DACK and DCS DMA modes?
Both DREQ/DACK mode and dedicated chip select (DCS) are DMA modes. DCS mode allows more control of the data through the FFTHRC register, since DREQ/DACK modes are fixed to single or the programmed burst sizes.
In DREQ/DACK DMA mode, the DREQ/ asserts as soon as sufficient data is present to fullfill the DMA burst or DMA single access settings in the EDMOD registers. DREQ/ assert should be answered with an DACK/ assert from the host processor.
DREQ/DACK mode and DCS mode require the DREQ/ and DACK/ pins. However, the functionality of these pins is slightly different in the two modes.
See the ADV212 Programming Guide for more information on DREQ/DACK and DCS DMA modes. See the ADV212 User's Guide for more information on the threshold registers.