Samsung SF-4500 Service Manual page 35

6-1-2-4 EXTERNAL DMA
It brings data from an external device (SCANIP:U18)
using DMA channel 0. DMA REQUEST sent from an
external device to KS32C6200 activates DMA
ACKNOWLEDGE signal and drives DMA channel 0
to produce CHIP SELECT and READ STROBE (/RD)
at the external
MCLK
/XDREQ
/XDACK
D[15:0]
/RD
/WR
6-4
Fig.6-1-4 EXTERNAL DMA TIMING DIAGRAM
device and bring data from it. It generates address of
destination memory, CHIP SELECT and WRITE
STROBE (/WR) in order to move this data into
destination memory, and then stores the data.
Samsung Electronics