ATmega168P Atmel Corporation, ATmega168P Datasheet - Page 260
ATmega168P
Manufacturer Part Number
ATmega168P
Description
Manufacturer
Atmel Corporation
Specifications of ATmega168P
Flash (kbytes)
16 Kbytes
Pin Count
32
Max. Operating Frequency
20 MHz
Cpu
8-bit AVR
# Of Touch Channels
16
Hardware Qtouch Acquisition
No
Max I/o Pins
23
Ext Interrupts
24
Usb Speed
No
Usb Interface
No
Spi
2
Twi (i2c)
1
Uart
1
Graphic Lcd
No
Video Decoder
No
Camera Interface
No
Adc Channels
8
Adc Resolution (bits)
10
Adc Speed (ksps)
15
Analog Comparators
1
Resistive Touch Screen
No
Temp. Sensor
Yes
Crypto Engine
No
Sram (kbytes)
1
Eeprom (bytes)
512
Self Program Memory
YES
Dram Memory
No
Nand Interface
No
Picopower
Yes
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
3
Output Compare Channels
6
Input Capture Channels
1
Pwm Channels
6
32khz Rtc
Yes
Calibrated Rc Oscillator
Yes
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24.9
24.9.1
260
Register Description
ATmega48P/88P/168P
ADMUX – ADC Multiplexer Selection Register
• Bit 7:6 – REFS1:0: Reference Selection Bits
These bits select the voltage reference for the ADC, as shown in
changed during a conversion, the change will not go in effect until this conversion is complete
(ADIF in ADCSRA is set). The internal voltage reference options may not be used if an external
reference voltage is being applied to the AREF pin.
Table 24-3.
• Bit 5 – ADLAR: ADC Left Adjust Result
The ADLAR bit affects the presentation of the ADC conversion result in the ADC Data Register.
Write one to ADLAR to left adjust the result. Otherwise, the result is right adjusted. Changing the
ADLAR bit will affect the ADC Data Register immediately, regardless of any ongoing conver-
sions. For a complete description of this bit, see
page
• Bit 4 – Res: Reserved Bit
This bit is an unused bit in the ATmega48P/88P/168P, and will always read as zero.
• Bits 3:0 – MUX3:0: Analog Channel Selection Bits
The value of these bits selects which analog inputs are connected to the ADC. See
for details. If these bits are changed during a conversion, the change will not go in effect until this
conversion is complete (ADIF in ADCSRA is set).
Bit
(0x7C)
Read/Write
Initial Value
REFS1
0
0
1
1
263.
REFS0
REFS1
Voltage Reference Selections for ADC
R/W
0
1
0
1
7
0
REFS0
Voltage Reference Selection
AREF, Internal V
AV
Reserved
Internal 1.1V Voltage Reference with external capacitor at AREF pin
R/W
6
0
CC
with external capacitor at AREF pin
ADLAR
R/W
5
0
ref
turned off
R
0
4
–
MUX3
R/W
”ADCL and ADCH – The ADC Data Register” on
3
0
MUX2
R/W
2
0
MUX1
R/W
1
0
Table
MUX0
R/W
0
0
24-3. If these bits are
ADMUX
8025M–AVR–6/11
Table 24-4