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ADC0801 Datasheet - Page 26

Download or read online National Semiconductor ADC0801 8-Bit Microprocessor Compatible A/D Converters pdf datasheet.
Also see for ADC0801: Datasheet #2 (41 pages)



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Functional Description
(Continued)
Note 1 Numbers in parentheses refer to MC6800 CPU pin out
Note 2 Numbers of letters in brackets refer to standard M6800 system common bus code
FIGURE 16 Interfacing Multiple A Ds in an MC6800 System
SAMPLE PROGRAM FOR FIGURE 16 INTERFACING MULTIPLE A Ds IN AN MC6800 SYSTEM
ADDRESS
HEX CODE
0010
DF 44
0012
CE 00 2A
0015
FF FF F8
0018
B7 50 00
001B
0E
001C
3E
001D
CE 50 00
0020
DF 40
0022
CE 02 00
0025
DF 42
0027
DE 44
0029
39
002A
DE 40
002C
A6 00
002E
08
002F
DF 40
0031
DE 42
MNEMONICS
COMMENTS
DATAIN
STX
TEMP
LDX
$002A
STX
$FFF8
STAA
$5000
CLI
WAI
LDX
$5000
STX
INDEX1
LDX
$0200
STX
INDEX2
LDX
TEMP
RTS
INTRPT
LDX
INDEX1
LDAA
X
INX
STX
INDEX1
LDX
INDEX2
26
TL H 5671 – 26
Save Contents of X
Upon IRQ LOW CPU
Jumps to 002A
Starts all A D’s
Wait for interrupt
Reset both INDEX
1 and 2 to starting
addresses
Return from subroutine
INDEX1
X
Read data in from A D at X
Increment X by one
X
INDEX1
INDEX2
X

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