ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 291

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 14
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 26
• Ext Interrupts: 13
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 12
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 3.3
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 2.7 to 5.5
• Operating Voltage (vcc): 2.7 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

23.1
23.1.1
7766F–AVR–11/10
Analog Comparator Multiplexed Input
Digital Input Disable Register 1 – DIDR1
It is possible to select any of the ADC13..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), and MUX2..0 in
ADMUX select the input pin to replace the negative input to the Analog Comparator, as shown in
Table
input to the Analog Comparator.
Table 23-2.
• Bit 0 – AIN0D: AIN0 Digital Input Disable
When this bit is written logic one, the digital input buffer on the AIN0 pin is disabled. The corre-
sponding PIN Register bit will always read as zero when this bit is set. When an analog signal is
applied to the AIN0 pin and the digital input from this pin is not needed, this bit should be written
logic one to reduce power consumption in the digital input buffer.
Bit
Read/Write
Initial Value
ACME
0
1
1
1
1
1
1
1
1
1
23-2. If ACME is cleared or ADEN is set, the Bandgap reference is applied to the negative
ADEN
7
–
R
0
Analog Comparator Multiplexed Input
x
1
0
0
0
0
0
0
0
0
6
–
R
0
MUX2..0
000
001
010
011
100
101
110
111
xxx
xxx
5
–
R
0
Analog Comparator Negative Input
Bandgap Ref.
Bandgap Ref.
ADC0
ADC1
N/A
ADC4
ADC5
ADC6
ADC7
4
–
R
0
3
–
R
0
2
–
R
0
1
–
R
0
ATmega16/32U4
0
AIN0D
R/W
0
DIDR1
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