ATMEGA8HVD-4MX Atmel, ATMEGA8HVD-4MX Datasheet - Page 96

• Manufacturer Part Number: ATMEGA8HVD-4MX
• Description: MCU AVR 8K FLASH 2.1-8V 4MHZ QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8HVD-4MX

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Peripherals: POR, WDT
• Number Of I /o: 5
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 2.4 V
• Data Converters: A/D 1x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 18-MLF® Exposed Pad (Staggered Leads), DFN
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Connectivity: -

17.7
17.7.1
96
ADC Conversion Result
ATmega4HVD/8HVD
Temperature Measurement using the internal temperature sensor – TBD
After the conversion is complete (ADIF is high), the conversion result can be found in the ADC
Result Registers (ADCL, ADCH).
For single ended conversion, the result is
where V
ground, and 0x3FF represents 5 times the reference voltage minus one LSB.
The temperature measurement is based on an on-chip temperature sensor that is coupled to a
single ended ADC channel. Selecting the ADC Temperature channel by writing the ADTEMP
bit in ADCSRA register enables the temperature sensor. When the temperature sensor is
enabled, the ADC converter can be used in single conversion mode to measure the voltage
over the temperature sensor. The measured voltage has a linear relationship to the tempera-
ture as described in
and the accuracy of the temperature measurement is +/- 10°C.
Table 17-2.
The values described in
cess variation the temperature sensor output voltage varies from one chip to another. To be
capable of achieving more accurate results the temperature measurement can be calibrated in
the application software. The software calibration requires that a calibration value is measured
and stored in a register or EEPROM for each chip, as a part of the production test. The sof-
ware calibration can be done utilizing the formula:
where V
1.07 mV/°C) and T
EEPROM as a part of production test.
Temperature (°C)
Voltage (mV)
IN
TEMP
is the voltage on input pin and V
is the ADC reading of the temperature sensor signal, k is a fixed coefficient (TBD,
Temperature vs. Sensor Output Voltage (Typical values)
OS
Table 17-2 on page
is the temperature sensor offset value determined and stored into
Table 17-2 on page 96
225 mV
Temperature
-45 °C
ADC
96. The voltage sensitivity is approximately 1 mV / °C
=
REF
V
--------------------------
=
5 V
IN
the voltage reference. 0x000 represents analog
⋅
k V
⋅
are typical values. However, due to the pro-
⋅
1024
REF
TEMP
297 mV
+27 °C
+
T
OS
+105 °C
327 mV
8052B–AVR–09/08