ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 256

• 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

21.4
21.5
7766F–AVR–11/10
Crystal-less operation
Design guidelines
Figure 21-6. Typical Self powered application with 3.0V to 3.6 I/O
To reduce external components count and BOM cost, the USB module can be configured to
operate in low-speed mode with internal RC oscillator as input source clock for the PLL. The
internal RC oscillator is factory calibrated to satisfy the USB low speed frequency accuracy
within the 0°C and -40°C temperature range.
For USB full-speed operation only external crystal oscillator or external source clock can be
used.
• Serial resistors on USB Data lines must have 22 Ohms value (
• Traces from the input USB receptable (or from the cable connection in the case of a tethered
• Voltage transient / ESD suppressors may also be used to prevent USB pads to be damaged
• U
• A 10µF capacitor is highly recommended on VBUS line
device) to the USB microcontroller pads should be as short as possible, and follow differential
traces routing rules (same length, as near as possible, avoid via accumulation).
by external disturbances.
cap
capacitor should be 1µF (
VBUS
UVSS
UDP
UDM
UID
Rs=22
Rs=22
1µF
+/-
10%) for correct operation.
UCAP
VBUS
UGND
D+
D-
UID
UVCC
XTAL1
XTAL2
AVCC
GND
VCC
GND
ATmega16/32U4
+/-
5%).
External 3.0V - 3.6V
Power Supply
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