ATtiny167 Atmel Corporation, ATtiny167 Datasheet - Page 203

• Manufacturer Part Number: ATtiny167
• Manufacturer: Atmel Corporation

Specifications of ATtiny167

• Flash (kbytes): 16 Kbytes
• Pin Count: 20
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 16
• Ext Interrupts: 16
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Lin: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 0.5
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 3
• Input Capture Channels: 1
• Pwm Channels: 9
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

17.9
17.10 Internal Voltage Reference Output
8265B–AVR–09/10
Temperature Measurement
However, if the signal is not bipolar by nature (9 bits + sign as the 10th bit), this scheme loses
one bit of the converter dynamic range. Then, if the user wants to perform the conversion with
the maximum dynamic range, the user can perform a quick polarity check of the result and use
the unipolar differential conversion with selectable differential input pair. When the polarity
check is performed, it is sufficient to read the MSB of the result (ADC9 in ADCH register). If the
bit is one, the result is negative, and if this bit is zero, the result is positive.
The temperature measurement is based on an on-chip temperature sensor that is coupled to a
single ended ADC input. MUX[4:0] bits in ADMUX register enables the temperature sensor.
The internal 1.1V voltage reference must also be selected for the ADC voltage reference
source in the temperature sensor measurement. When the temperature sensor is enabled, the
ADC converter can be used in single conversion mode to measure the voltage over the tem-
perature sensor.
The measured voltage has a linear relationship to the temperature as described in
The sensitivity is approximately 1 LSB / °C and the accuracy depends on the method of user
calibration. Typically, the measurement accuracy after a single temperature calibration is
±
two temperature points for calibration.
Table 17-2.
The values described in
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 soft-
ware. The sofware calibration can be done using the formula:
where ADCH and ADCL are the ADC data registers, T is temperature in Kelvin, k is the fixed
slope coefficient and T
in single-point calibration the coefficient may be omitted. Where higher accuracy is required
the slope coefficient should be evaluated based on measurements at two temperatures.
The internal voltage reference is output on XREF pin as described in
turned on
of an external filter capacitor (5 - 10 nF) on XREF pin may be necessary. XREF current load
must be from 1 µA to 100 µA with V
4.5V to 5.5V for XREF = 2.56V.
10
°C, assuming calibration at room temperature. Better accuracies are achieved by using
Temperature/°C
T = k * [(ADCH << 8) | ADCL] + T
(See “Voltage Reference Enable Signals and Start-up Time” on page
Temperature vs. Sensor Output Voltage (Typical Case): Example ADC Values
OS
Table 17-2
is the temperature sensor offset. Typically, k is very close to 1.0 and
0x00F6
–40°C
are typical values. However, due to process variation the
CC
from 2.7V to 5.5V for XREF = 1.1V and with V
OS
0x0144
+25°C
Table 17-3
0c01B8
+85°C
53.). Addition
if the ADC is
Table 17-2
CC
from
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