Intel 80C188XL - Manual (Page 277)

DIRECT MEMORY ACCESS UNIT
10-22
10.3.4 Generating a DMA Acknowledge
The DMA channels do not provide a distinct DMA acknowledge signal. A chip-select line can be
programmed to activate for the memory or I/O range that requires the acknowledge. The chip-
select must be programmed to activate only when a DMA is in progress. Latched status line S6
can be used as a qualifier to the chip-select for situations in which the chip-select line will be ac-
tive for both DMA and normal data accesses.
10.4 DMA UNIT EXAMPLES
Example 10-1 sets up channel 0 to perform an unsynchronized burst transfer from memory to
memory while channel 1 is used to service an external DMA request from a hard disk controller.
Example 10-2 shows timed DMA transfers. A sawtooth waveform is created using DMA trans-
fers to an A/D converter.