Samsung SF4500, Service Manual

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6-4 Samsung Electronics
6-1-2-4 EXTERNAL D M A
It brings data from an external device (SCANIP:U18)
using DMAchannel 0. DMAREQUEST sent from an
external device to KS32C6200 activates DMA
ACKNOWLEDGE signal and drives DMAchannel 0
to produce CHIP SELECT and READ STROBE (/RD)
at the external 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.
Fig.6-1-4 EXTERNAL DMA TIMING DIAGRAM