ADC838 National Semiconductor Corporation, ADC838 Datasheet - Page 20

• Manufacturer Part Number: ADC838
• Description: ADC0831 - 8-Bit Serial I/o A/D Converter With Multiplexer Option, Package: Soic Wide, Pin Nb=14
• Manufacturer: National Semiconductor Corporation

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Applications
Cop Coding Example
LEI
SC
OGI
CLR A
AISC 1
XAS
LDD
NOP
XAS
XAS
XIS
CLR A
RC
XAS
XIS
OGI
LEI
Mnemonic
ENABLES SIO’s INPUT AND OUTPUT
C = 1
G0=0 (CS =0)
CLEARS ACCUMULATOR
LOADS ACCUMULATOR WITH 1
EXCHANGES SIO WITH ACCUMULATOR
AND STARTS SK CLOCK
LOADS MUX ADDRESS FROM RAM
INTO ACCUMULATOR
LOADS MUX ADDRESS FROM
ACCUMULATOR TO SIO REGISTER
READS HIGH ORDER NIBBLE (4 BITS)
INTO ACCUMULATOR
PUTS HIGH ORDER NIBBLE INTO RAM
CLEARS ACCUMULATOR
C = 0
READS LOW ORDER NIBBLE INTO
ACCUMULATOR AND STOPS SK
PUTS LOW ORDER NIBBLE INTO RAM
G0=1 (CS =1)
DISABLES SIO’s INPUT AND OUTPUT
—
8 INSTRUCTIONS
(Continued)
Instruction
↑
↓
20
8048 CODING EXAMPLE
START:
LOOP 1:
ZERO:
ONE:
CONT:
LOOP 2:
RETR
PULSE:
Mnemonic
ANL
MOV
MOV
RRC
JC
ANL
JMP
ORL
CALL
DJNZ B, LOOP 1 ;CONTINUE UNTIL
CALL
MOV
CALL
IN
RRC
RRC
MOV
RLC
MOV
DJNZ B, LOOP 2 ;CONTINUE UNTIL
ORL
NOP
ANL
RET
P1, # 0F7H ;SELECT A/D (CS =0)
B, # 5
A, # ADDR ;A ← MUX ADDRESS
A
ONE
P1, # 0FEH ;DI ← 0
CONT
P1, # 1
PULSE
PULSE
B, # 8
PULSE
A, P1
A
A
A, C
A
C, A
P1, # 04
P1, # 0FBH ;SK ← 0
;BIT COUNTER ← 5
;CY ← ADDRESS BIT
;TEST BIT
;BIT=0
;CONTINUE
;BIT=1
;DI ← 1
;PULSE SK 0 → 1 → 0
DONE
;EXTRA CLOCK FOR
SYNC
;BIT COUNTER ← 8
;PULSE SK 0 → 1 → 0
;CY ← DO
;A ← RESULT
;A(0) ← BIT AND SHIFT
;C ← RESULT
DONE
;PULSE SUBROUTINE
;SK ← 1
;DELAY
Instruction