ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 289

• 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. Analog Comparator
23.0.1
23.0.2
7766F–AVR–11/10
ADC Control and Status Register B – ADCSRB
Analog Comparator Control and Status Register – ACSR
The Analog Comparator compares the input values on the positive pin AIN+ and negative pin
AIN-. When the voltage on the positive pin AIN+ is higher than the voltage on the negative pin
AIN-, 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
Bandgap reference. AIN- can only be connected to the ADC multiplexer.
The Power Reduction ADC bit, PRADC, in
must be disabled by writing a logical zero to be able to use the ADC input MUX.
Figure 23-1. Analog Comparator Block Diagram
Notes:
• Bit 6 – ACME: Analog Comparator Multiplexer Enable
When this bit is written logic one and the ADC is switched off (ADEN in ADCSRA is zero), the
ADC multiplexer is connected to the negative input to the Analog Comparator. When this bit is
written logic zero, the Bandgap reference is connected to the negative input of the Analog Com-
parator
“Analog Comparator Multiplexed Input” on page
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
ADC MULTIPLEXER
(See “Internal Voltage Reference” on page
1. See
2. Refer to
Figure
REFERENCE
REFERENCE
ACME
ADEN
BANDGAP
BANDGAP
OUTPUT
log Comparator pin placement.
7
ADHSM
R
0
7
ACD
R/W
0
Table 23-2 on page
(1)
23-1. AIN+ can be connected either to the AIN0 (PE6) pin, or to the internal
ACBG
“Pinout ATmega16U4/ATmega32U4” on page 3
6
ACBG
R/W
0
6
ACME
R/W
0
5
ACO
R
N/A
AIN+
AIN-
5
MUX5
R
0
291.
4
ACI
R/W
0
4
–
R
0
“Power Reduction Register 0 - PRR0” on page 46
3
ACIE
0
R/W
3
ADTS3
R
0
291.
(2)
54.). For a detailed description of this bit, see
2
ACIC
R/W
0
2
ADTS2
R/W
0
and
1
ACIS1
R/W
0
1
ADTS1
R/W
0
ATmega16/32U4
Table 10-3 on page 72
0
ACIS0
R/W
0
0
ADTS0
R/W
0
ACSR
ADCSRB
for Ana-
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