ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 262

• 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

21.11 Plug-in detection
7766F–AVR–11/10
Figure 21-12. Pad behaviour
The SUSPI flag indicated that a suspend state has been detected on the USB bus. This flag
automatically put the USB pad in Idle. The detection of a non-idle event sets the WAKEUPI flag
and wakes-up the USB pad.
Moreover, the pad can also be put in the “idle” mode if the DETACH bit is set. It come back in
the active mode when the DETACH bit is cleared.
The USB connection is detected by the VBUS pad, thanks to the following architecture:
SUSPI
WAKEUPI
PAD status
Active
Suspend detected = USB pad power down
Idle mode
Resume = USB pad wake-up
| DETACH=1
| suspend
USBE=0
Power Down
& DETACH=0
& suspend
USBE=1
Clear Suspend by software
Clear Resume by software
Active mode
Active
ATmega16/32U4
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