ATmega325P Atmel Corporation, ATmega325P Datasheet - Page 203

• Manufacturer Part Number: ATmega325P
• Manufacturer: Atmel Corporation

Specifications of ATmega325P

• Flash (kbytes): 32 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 17
• 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: No
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 1024
• 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: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

20. Analog Comparator
20.1
20.2
8023F–AVR–07/09
Overview
Analog Comparator Multiplexed Input
The Analog Comparator compares the input values on the positive pin AIN0 and negative pin
AIN1. When the voltage on the positive pin AIN0 is higher than the voltage on the negative pin
AIN1, the Analog Comparator output, ACO, is set. The comparator’s output can be set to trigger
the Timer/Counter1 Input Capture function. In addition, the comparator can trigger a separate
interrupt, exclusive to the Analog Comparator. The user can select Interrupt triggering on com-
parator output rise, fall or toggle. A block diagram of the comparator and its surrounding logic is
shown in
The PRADC, in
the ADC input MUX.
Figure 20-1. Analog Comparator Block Diagram
Note:
It is possible to select any of the ADC7:0 pins to replace the negative input to the Analog Com-
parator. The ADC multiplexer is used to select this input, and consequently, the ADC must be
switched off to utilize this feature. If the Analog Comparator Multiplexer Enable bit (ACME in
ADCSRB) is set and the ADC is switched off (ADEN in ADCSRA is zero), MUX2:0 in ADMUX
select the input pin to replace the negative input to the Analog Comparator, as shown in
20-1. If ACME is cleared or ADEN is set, AIN1 is applied to the negative input to the Analog
Comparator.
Table 20-1.
ACME
0
1
1
ADC MULTIPLEXER
1. See
2. Refer to
Figure
REFERENCE
ACME
ADEN
BANDGAP
OUTPUT
page 75
Analog Comparator Multiplexed Input
Table 20-1 on page
(1)
”PRR – Power Reduction Register” on page 44
20-1.
ADEN
ACBG
x
1
0
Figure 1-1 on page
for Analog Comparator pin placement.
MUX2:0
000
xxx
xxx
203.
2,
Figure 1-2 on page
Analog Comparator Negative Input
AIN1
AIN1
ADC0
(2)
3and
ATmega325P/3250P
”Alternate Functions of Port E” on
must be written to zero to use
Table
203