Intel 80C188XL User Manual

Page 280

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10-25

DIRECT MEMORY ACCESS UNIT

Example 10-1. Initializing the DMA Unit (Continued)

MOV

AX, 512

; THE DISK READS IN 512 BYTE

SECTORS

MOV

DX, D1TC

; XFER COUNT REG

OUT

DX, AX

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

SOURCE

; -----------

------

;

MEMORY SPACE

I/O SPACE

;

INCREMENT PTR

CONSTANT PTR

;
; TERMINATE ON TC, INTERRUPT, SOURCE SYNC, HIGH PRIORITY RELATIVE TO
; CHANNEL 0, BYTE XFERS, USE DRQ PIN FOR REQUEST SOURCE. ARM CHANNEL.

MOV

AX, 1010001101100110B

MOV

DX, D0CON

OUT

DX, AX

; REQUESTS ON DRQ1 WILL NOW RESULT IN TRANSFERS

CODE_SEG

ENDS

DATA_SEG

SEGMENT

SOURCE_DATA_1DB '80C186EC INTEGRATED PROCESSOR'
DEST_DATA_1DB

30 DUP('MITCH')

; JUNK DATA FOR TEST

DISK_BUFF DB

512 DUP(?)

DATA_SEG

ENDS
END START

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