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ADC0801 Datasheet - Page 21

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
Pin numbers for the DP8228 system controller others are INS8080A
Note 2 Pin 23 of the INS8228 must be tied to
instruction when an interrupt is acknowledged as required by the accompanying sample program
FIGURE 10 ADC0801– INS8080A CPU Interface
SAMPLE PROGRAM FOR FIGURE 10 ADC0801 – INS8080A CPU INTERFACE
0038
C3 00 03
RST 7
0100
21 00 02
START
0103
31 00 04
RETURN
0106
7D
0107
FE OF
0109
CA 13 01
010C
D3 E0
010E
FB
010F
00
LOOP
0110
C3 OF 01
0113
CONT
(User program to
process data)
0300
DB E0
LD DATA
0302
77
0303
23
0304
C3 03 01
Note 1 The stack pointer must be dimensioned because a RST 7 instruction pushes the PC onto the stack
Note 2 All address used were arbitrarily chosen
12V through a 1 k
resistor to generate the RST 7
a
JMP
LD DATA
LXI H 0200H
HL pair will point to
data storage locations
LXI SP 0400H
Initialize stack pointer (Note 1)
MOV A L
Test
of bytes entered
CPI OF H
If
16 JMP to
JZ CONT
user program
OUT E0 H
Start A D
EI
Enable interrupt
NOP
Loop until end of
JMP LOOP
conversion
IN E0 H
Load data into accumulator
MOV M A
Store data
INX H
Increment storage pointer
JMP RETURN
21
TL H 5671 – 20

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