atmega32u4-16mu ATMEL Corporation, atmega32u4-16mu Datasheet - Page 319

• Manufacturer Part Number: atmega32u4-16mu
• Description: Atmega32u4 8-bit Avr Microcontroller With 32k Bytes Of Isp Flash And Usb Controller
• Manufacturer: ATMEL Corporation

25.6.2
25.7
7766A–AVR–03/08
ADC Noise Canceler
Temperature Sensor Control Register – TSENSE
tor Calibration Register – OSCCAL” on page
two temperatures (+25°C and +85°C, with a tolerance of +/-10°C
temperature sensor value T
calibration value O
have an accurate 8MHz output) is stored in another memory zone.
Thanks to these four values and the linear characteristics of the temperature sensor and Internal
RC Oscillator, firmware can easily recalibrate the RC Oscillator on-the-go in function of the tem-
perature sensor measure
Figure 25-8. Linear Characterization of OSCCAL in function of T° measurement from ADC
Notes:
• Bit 7-1 – Reserved
Do not set these bits. Read value should be ‘0’.
• Bit 0 – TSEN: Temperature Sensor Enable
Writing this bit to one enables the Temperature Sensor. This bit may be cleared if the sensor is
not used to avoid extra-consumption.
The ADC features a noise canceler that enables conversion during sleep mode to reduce noise
induced from the CPU core and other I/O peripherals. The noise canceler can be used with ADC
Noise Reduction and Idle mode. To make use of this feature, the following procedure should be
used:
Bit
Read/Write
Initial Value
1. The temperature sensor calibration values cannot be used to do accurate temperature mea-
2. Be aware that if EESAVE fuse is left unprogrammed, any chip erase operation will
3.
surements since the calibration temperature during production is not accurate (+/- 10°C)
clear the temperature sensor calibration values contained in EEPROM memory.
Accuracy results after a software recalibration of OSCCAL in function of T° will be
given when device will be fully characterized.
R/W
OSCCAL
O
O
7
0
-
2
1
i
(i.e. the value that should be set in OSCCAL register at this temperature to
R/W
6
0
-
(3)
(an application note describes the operation):
i
is measured and stored in EEPROM memory
R/W
5
0
-
T
1
R/W
4
0
-
T
2
31). During the production, a calibration is done at
T (ADC
R/W
3
0
-
R/W
2
0
-
R/W
1
0
-
(1)
). At each temperature, the
TSEN
ATmega32U4
R/W
0
0
(2)
, and the OSCCAL
TSENSE
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