Data Sheet

967
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181G–SAM-D21_Datasheet–09/2015
z ROOM_INT1V_VAL is denoted INT1V
R
z HOT_INT1V_VAL is denoted INT1V
H
Using the (temp
R
, ADC
R
) and (temp
H
, ADC
H
) points, using a linear interpolation we have the following equation:
Given a temperature sensor ADC conversion value ADC
m
, we can infer a coarse value of the temperature temp
C
as:
[Equation 1]
Notes: 1. In the previous expression, we’ve added the conversion of the ADC register value to be expressed in V.
2. This is a coarse value because we assume INT1V=1V for this ADC conversion.
Using the (temp
R
, INT1V
R
) and (temp
H
, INT1V
H
) points, using a linear interpolation we have the following equation:
Then using the coarse temperature value, we can infer a closer to reality INT1V value during the ADC conversion as:
Back to [Equation 1], we replace INT1V=1V by INT1V = INT1V
m
, we can then deduce a finer temperature value as:
[Equation 1bis]
V
ADC
V
ADCR
–
temp temp
R
–
-------------------------------------
⎝⎠
⎛⎞
V
ADCH
V
ADCR
–
temp
H
temp
R
–
----------------------------------------
⎝⎠
⎛⎞
=
temp
C
temp
R
ADC
m
1
2
12
1–()
---------------------
⋅
⎝⎠
⎛⎞
ADC
R
INT1V
R
2
12
1–()
---------------------
⋅
⎝⎠
⎜⎟
⎛⎞
–
⎩⎭
⎨⎬
⎧⎫
temp
H
temp
R
–()⋅
ADC
H
INT1V
H
2
12
1–()
---------------------
⋅
⎝⎠
⎜⎟
⎛⎞
ADC
R
INT1V
R
2
12
1–()
---------------------
⋅
⎝⎠
⎜⎟
⎛⎞
–
⎩⎭
⎨⎬
⎧⎫
------------------------------------------------------------------------------------------------------------------------------------------------------------
+=
INT1VINT1V
R
–
temp temp
R
–
-------------------------------------------
⎝⎠
⎛⎞
INT1V
H
INT1V
R
–
temp
H
temp
R
–
-----------------------------------------------
⎝⎠
⎛⎞
=
INT1V
m
INT1V
R
INT1V
H
INT1V
R
–()temp
C
temp
R
–()⋅
temp
H
temp
R
–()
---------------------------------------------------------------------------------------------------
⎝⎠
⎛⎞
+=
temp
f
temp
R
ADC
m
INT1V
m
2
12
1–()
---------------------
⋅
⎝⎠
⎜⎟
⎛⎞
ADC
R
INT1V
R
2
12
1–()
---------------------
⋅
⎝⎠
⎜⎟
⎛⎞
–
⎩⎭
⎨⎬
⎧⎫
temp
H
temp
R
⋅()⋅
ADC
H
INT1V
H
2
12
1–()
---------------------
⋅
⎝⎠
⎜⎟
⎛⎞
ADC
R
INT1V
R
2
12
1–()
---------------------
⋅
⎝⎠
⎜⎟
⎛⎞
–
⎩⎭
⎨⎬
⎧⎫
----------------------------------------------------------------------------------------------------------------------------------------------------------
+=