Interfacing with LM35 and display temperature in 7 Segment Display

Atmel 8051 microcontroller (asm source code)

How to interface with LM35 temperature sensor

Convert ADC value to temperature

Display temperature into 7 segment display

;======================================================================
; Global variables
;======================================================================

SEVENSEGMENT EQU P0
K1 EQU P1.0
K2 EQU P1.1
INCSWITCH EQU P1.2
DECSWITCH EQU P1.3
BUZZER EQU P1.4
ADC_RD EQU P3.0
ADC_WR EQU P3.1
ADC_INTR EQU P3.2
FAN EQU P3.3

DisplayTemp:

mov DPTR,#Tens ;use lookup table to show tens
MOv A,R3 ;get value from ADC
Movc A,@A+DPTR ;compare value in lookup table
mov R4,A ;collect data for checkspeed
Mov DPTR,#Decoder7Segment ;use lookup table
Movc A,@A+DPTR ;compare value in lookup table
mov SEVENSEGMENT, #0 ;clear seven segment display
clr K1 ;select display 1
setb K2
Mov SEVENSEGMENT,A ;send data to seven segment display

mov DPTR,#Ones ;use lookup table to show ones
MOv A,R3 ;get value from ADC
Movc A,@A+DPTR ;compare value in lookup table
Mov DPTR,#Decoder7Segment ;use lookup table
Movc A,@A+DPTR ;compare value in lookup table
mov SEVENSEGMENT, #0 ;clear seven segment display
setb K1 ;select display 2
clr K2
Mov SEVENSEGMENT,A ;7seg

ret

;======================================================================
; Lookup Table
; Decoder to Seven Segment
;======================================================================

Decoder7Segment:
DB 00111111b,00000110b,01011011b,01001111b,01100110b
DB 01101101b,01111101b,00000111b,01111111b,01101111b

;======================================================================
; Lookup Table
; Temperature = DataADC*100/255
;======================================================================

Ones:
db 0,0,0,1,1,2,2,2,3,3,3,4,4,5,5,5,6,6,7,7,7,8,8,9,9,9,0,0,1,1,1,2,2,2,3,3,4,4,4,5,5,6,6,6,7,7,8,8,8,9,9
db 0,0,0,1,1,2,2,2,3,3,3,4,4,5,5,5,6,6,7,7,7,8,8,9,9,9,0,0,1,1,1,2,2,2,3,3,4,4,4,5,5,6,6,6,7,7,8,8,8,9
db 9,0,0,0,1,1,2,2,2,3,3,3,4,4,5,5,5,6,6,7,7,7,8,8,9,9,9,0,0,1,1,1,2,2,2,3,3,4,4,4,5,5,6,6,6,7,7,8,8,8
db 9,9,0,0,0,1,1,2,2,2,3,3,3,4,4,5,5,5,6,6,7,7,7,8,8,9,9,9,0,0,1,1,1,2,2,2,3,3,4,4,4,5,5,6,6,6,7,7,8,8
db 8,9,9,0,0,0,1,1,2,2,2,3,3,3,4,4,5,5,5,6,6,7,7,7,8,8,9,9,9,0,0,1,1,1,2,2,2,3,3,4,4,4,5,5,6,6,6,7,7,8,8,8,9,9,0

Tens:
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1
db 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3,3
db 3,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5
db 5,5,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
db 7,7,7,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,0

end

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