
Data Sheet
ADuC7023
| Page 35 of 96
The ADCCON register must be configured to 0x37A3.
To calculate die temperature use the following formula:
T TREF = (VADC VTREF) × K
where:
T is the temperature result.
TREF is 25°C.
VADC is the average ADC result from two consecutive
conversions.
VTREF is 1369 mV, which corresponds to TREF = 25°C as
K is the gain of the ADC in temperature sensor mode as
determined by characterization data, K = 0.2262°C/mV. This
corresponds to 1/V TC specification as shown
in Table 1.Using the default values from
Table 1 and without any calibra-
tion, this equation becomes
T – 25°C = (VADC 1369) × 0.2262
where:
VADC is in millivolts.
For increased accuracy, perform a single point calibration at a
controlled temperature value.
For the calculation shown without calibration, (TREF, VTREF) =
(25°C, 1369 mV). The idea of a single point calibration is to use
other known (TREF, VTREF) values to replace the common (25°C,
1369 mV) for every part.
For some users, it is not possible to get such a known pair. For
these cases, an ADuC7023 comes with a single point calibration
value loaded in the TEMPREF register. For more details on this
During production testing of the ADuC7023, the TEMPREF
register is loaded with an offset adjustment factor. Each part
will have a different value in the TEMPREF register. Using this
single point calibration, use the same formula as shown:
T TREF = (VADC VTREF) × K
where:
TREF is 27°C when using the TEMPREF register method, but is
not guaranteed.
TTREF can be calculated using the TEMPREF register.
TSCON Register
Name:
TSCON
Address:
0xFFFF0544
Default value:
0x00
Access:
Read/write
Table 28. TSCON MMR Bit Designations
Bit
Description
7 to 1
Reserved.
0
Temperature sensor chop enable bit.
This bit is set to 1 to enable chopping of the internal
amplifier to the ADC.
This bit is cleared to disable chopping.
This bit is cleared by default.
TEMPREF Register
Name:
TEMPREF
Address:
0xFFFF0548
Default value:
Factory configured
Access:
Read/write
Table 29. TEMPREF MMR Bit Designations
Bit
Description
15 to 9
Reserved.
8
Temperature reference voltage sign.
7 to 0
Temperature sensor offset calibration voltage.
To calculate the VTREF from the TEMPREF register,
perform the following calculation:
If TEMPREF sign negative, subtract TEMPREF from 2292
CTREF
= 2292 TEMPREF[7:0]
where TEMREF[8] = 1.
or
If TEMREF sign positive, add TEMPREF to 2292
CTREF = TEMPREF[7:0] + 2292
where:
TEMPREF[8] = 0.
Then,
VTREF
= (CTREF × VREF)/4096 × 1000
where:
CTREFis calculated as above.
VREF is 2.5 V, internal reference voltage.
Insert VTREF into
T – TREF = (VADC – VTREF) × K
where:
TREF is 27°C, when using TEMREF register.
VADC is the average ADC result from two
consecutive conversions.
VTREF is calculated as above.
Note that ADC code value 2292 is a default value
when using the TEMREF register. It is not an exact
value and must only be used with the TEMPREF
register.
Rev. E