2.5.3. Simulating to Display Temperature by Using Look Up Table

WHAT IS THE LOOK UP TABLE ?

Why do we need a look up tabel ? Look up tabel is just couple data that safe in ROM and it’s used to manipulate data. So we can avoid a very confusing prosess of math. In this case we are going to display temperature with three digit and one digit after point.

Temp = DataADC * 100/ 255 oC.

Note : DataADC is data that came from ADC, and have range 0-255, in this simple task, we assume that we use temperature range from 0 – 100 oC, so you just divide 100 by 255 as you look in table below.

After you made the tabel by using Microsoft Exell, now you should write down the data int the look up table:

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

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
db 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
db 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
db 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
db 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
db 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
db 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
db 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
db 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,
db 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
db 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

Hundreds :
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
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
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
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
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,
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
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
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
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
db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1

our plan is display the data as look like this for example: