ATMEGA8U2-AUR Atmel, ATMEGA8U2-AUR Datasheet - Page 195

• Manufacturer Part Number: ATMEGA8U2-AUR
• Description: MCU AVR 8K FLASH 16MHZ 32TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8U2-AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 22
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-TQFP, 32-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Converters: -

20.10 Registers Description
20.10.1
20.10.2
7799D–AVR–11/10
USBCON – USB General Control Registers
UPOE – USB Software Output Enable register
Resuming the USB interface
• Bit 7 – USBE: USB macro Enable Bit
Writing this bit to one enables the USB controller and the USB data buffers (D+ and D-). Clear-
ing this bit disables the USB controller and buffers. When cleared the USB controller is reset.
• Bit 6 – Res: Reserved
This bit is reserved and should always read as zero.
• Bit 5 – FRZCLK: Freeze USB Clock Bit
Writing this bit to one disables the internal clock for the USB controller, and tehreby freezing it.
Activating this mode reduces power consumption. All the USB flags are kept unchanged. Only
the “Resume detection” is still active in this mode.
Writing this bit to zero unfreezes the USB controller and allows full operation of the USB
interface.
• Bits 4:0 – Res: Reserved
These bits are reserved and should always read as zero.
• Bit 7:6 – UPWE[1:0]: USB Buffers Direct Drive enable configuration
These bits select the mode of operation of the USB buffers according to
ble configurations of these bits allows to enable or disable the USB buffers direct drive by soft-
ware. When direct drive for USB buffers is enable, the UPDRV[1:0] values are output to the
Bit
Read/Write
Initial Value
Bit
(0xFB)
Read/Write
Initial Value
• Be sure to have interrupts enabled (WAKEUPE) to exit sleep mode
• Put the MCU in sleep mode
• Enable PLL
• Wait PLL lock
• Clear USB suspend clock
• Clear Resume information
(0xD8)
USBE
UPWE1
R/W
R/W
7
0
7
0
UPWE0
R/W
R
6
0
-
6
0
FRZLK
UPDRV1
R/W
R/W
5
1
5
0
UPDRV0
R/W
R
4
0
-
4
0
ATmega8U2/16U2/32U2
R
3
0
R
3
0
-
-
R
R
2
0
2
0
-
-
DPI
R
1
0
R
1
0
-
Table
20-2. The possi-
DMI
0
R
0
R
0
0
-
USBCON
UPOE
195