ADC0831-N Datasheet, PDF (21/35 Pages) Texas Instruments – ADC0831/ADC0832/ADC0834/ADC0838 8-Bit Serial I/O A/D Converters with Multiplexer Options

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