ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 302

• 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

24.7.2
7766F–AVR–11/10
Analog Noise Canceling Techniques
Figure 24-9. Analog Input Circuitry
Digital circuitry inside and outside the device generates EMI which might affect the accuracy of
analog measurements. If conversion accuracy is critical, the noise level can be reduced by
applying the following techniques:
Figure 24-10. ADC Power Connections
Note:
a. Keep analog signal paths as short as possible. Make sure analog tracks run over
b. The AV
c. Use the ADC noise canceler function to reduce induced noise from the CPU.
d. If any ADC port pins are used as digital outputs, it is essential that these do not
The same circuitry should be used for AVCC filtering on the ADC8-ADC13 side
the analog ground plane, and keep them well away from high-speed switching digi-
tal tracks.
via an LC network as shown in
switch while a conversion is in progress.
CC
pin on the device should be connected to the digital V
ADCn
Analog Ground Plane
100nF
I
IH
Figure
I
IL
(ADC7) PF7
(ADC6) PF6
(ADC5) PF5
(ADC4) PF4
(ADC1) PF1
(ADC0) PF0
24-10.
AVCC
AREF
GND
GND
VCC
1..100 kΩ
34
35
36
37
38
39
40
41
42
43
44
1
ATmega16/32U4
C
S/H
= 14 pF
V
CC
CC
/2
supply voltage
302