Intel 80C188XL User Manual

Page 282

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10-27

DIRECT MEMORY ACCESS UNIT

Example 10-2. Timed DMA Transfers (Continued)

; NOW WE NEED TO SET THE PARAMETERS FOR THE CHANNEL AS FOLLOWS:
;
;

DESTINATION

SOURCE

;

-----------

------

;

I/O SPACE

MEMORY SPACE

;

CONSTANT PTR

INCREMENT PTR

;
; TERMINATE ON TC, INTERRUPT, SOURCE SYNCHRONIZE, INTERNAL REQUESTS,
; LOW PRIORITY RELATIVE TO CHANNEL 1, BYTE XFERS.

MOV

AX, 0001011101010110B

MOV

DX, D0CON

OUT

DX, AX

; NOW WE ASSUME THAT TIMER 2 HAS BEEN PROPERLY PROGRAMMED FOR A 22uS DELAY.
; WHEN THE TIMER IS STARTED, A DMA TRANSFER WILL OCCUR EVERY 22uS.

CODE_SEG

ENDS

DATA_SEG

SEGMENT

WAVEFORM_DATADB 0,1,2,3,4,5,6,7,8,9,10,11,12,13

DB

14,15,16,17,18,19,20,21,22,23,24

; ETC., UP TO 255

DATA_SEG

ENDS

END START

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