ATmega16U4 Atmel Corporation, ATmega16U4 Datasheet - Page 263

• Manufacturer Part Number: ATmega16U4
• Manufacturer: Atmel Corporation

Specifications of ATmega16U4

• Flash (kbytes): 16 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): 2.1
• Eeprom (bytes): 512
• 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

21.12 Registers description
21.12.1
7766F–AVR–11/10
USB general registers
Figure 21-13. Plug-in Detection Input Block Diagram
The control logic of the VBUS pad outputs a signal regarding the VBUS voltage level:
• 7-1 – Reserved
These bits are reserved. Do not modify these bits.
• 0 – UVREGE: USB pad regulator Enable
Set to enable the USB pad regulator. Clear to disable the USB pad regulator.
• 7 – USBE: USB macro Enable Bit
Set to enable the USB controller. Clear to disable and reset the USB controller, to disable the
USB transceiver and to disable the USB controller clock inputs.
• 6 – Reserved
The value read from these bits is always 0. Do not set these bits.
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
• The “Session_valid” signal is active high when the voltage on the UVBUS pad is higher or
• The VBUS status bit is set when “Session_valid” signal is active (VBUS > 1.4V).
• The VBUSTI flag is set each time the VBUS state changes.
• The USB peripheral cannot attach to the bus while VBUS bit is not set.
equal to 1.4V. If lower than 1.4V, the signal is not active.
VBUS
USBE
R/W
R/W
7
0
7
0
-
R/W
R/W
0
6
-
6
0
-
Pad logic
FRZCLK
R/W
VDD
VSS
R
5
0
5
1
-
OTGPADE
R/W
Session_valid
R/W
4
0
-
4
0
R
3
0
-
R
3
0
-
USBSTA.0
VBUS
R
2
0
-
R
2
0
-
R
R/W
1
0
ATmega16/32U4
-
1
0
-
UVREGE
VBUSTE
R/W
R/W
0
0
0
0
VBUSTI
USBINT.0
UHWCON
USBCON
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