Give the register organization of 8257?
The 8257 do the DMA operation over four independent DMA channels. Each of the four channels of 8257 has a couple of two 16-bit registers. DMA address register and terminal count register. Also, there are two ordinary registers for all the channels; namely, mode set registers and status register. Therefore there are a total of ten registers. The CPU selects one of these ten registers using address lines A0- A3.