ATmega324PA Atmel Corporation, ATmega324PA Datasheet - Page 244

• Manufacturer Part Number: ATmega324PA
• Manufacturer: Atmel Corporation

Specifications of ATmega324PA

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 32
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 3
• Twi (i2c): 1
• Uart: 2
• 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: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

Figure 23-1. Analog-to-digital Converter Block Schematic
23.3
8272C–AVR–06/11
BANDGAP (1.1V)
ADC[7:0]
REFERENCE
REFERENCE
(1.1V/2.56V)
INTERNAL
AVCC
AREF
Operation
GND
8-BIT DATABUS
ADC[2:0]
The ADC converts an analog input voltage to a 10-bit digital value through successive approxi-
mation. The minimum value represents GND and the maximum value represents the voltage on
the AREF pin minus 1 LSB. Optionally, AVCC or an internal 2.56V reference voltage may be
connected to the AREF pin by writing to the REFSn bits in the ADMUX Register. The internal
voltage reference may thus be decoupled by an external capacitor at the AREF pin to improve
noise immunity.
The analog input channel and differential gain are selected by writing to the MUX bits in
ADMUX. Any of the ADC input pins, as well as GND and a fixed bandgap voltage reference, can
be selected as single ended inputs to the ADC. A selection of ADC input pins can be selected as
positive and negative inputs to the differential gain amplifier.
If differential channels are selected, the differential gain stage amplifies the voltage difference
between the selected input channel pair by the selected gain factor. This amplified value then
ADC MULTIPLEXER
SELECT (ADMUX)
INPUT
INPUT
NEG
MUX
POS
MUX
MUX DECODER
ATmega164A/PA/324A/PA/644A/PA/1284/P
+
-
REGISTER B (ADCSRB)
ADC CTRL & STATUS
AMPLIFIER
GAIN
10-bit DAC
REGISTER A (ADCSRA)
ADC CTRL & STATUS
ADC CONVERSION
COMPLETE IRQ
PRESCALER
CONVERSION LOGIC
+
-
ADTS[2:0]
START
TRIGGER
SELECT
SAMPLE & HOLD
INTERRUPT
COMPARATOR
ADC
MULTIPLEXER
OUTPUT
FLAGS
15
ADC DATA REGISTER
(ADCH/ADCL)
0
244