ATMEGA16U4-MU Atmel, ATMEGA16U4-MU Datasheet - Page 281

• Manufacturer Part Number: ATMEGA16U4-MU
• Description: MCU AVR 16K FLASH 16MHZ 44-QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA16U4-MU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
• Number Of I /o: 26
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 1.25K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-VQFN
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATAVRDRAGON - KIT DRAGON 32KB FLASH MEM AVRATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATMEGA16U4-16MU; ATMEGA16U4-16MU

22.18.2
7766F–AVR–11/10
USB device endpoint registers
• Frame Number Lower Value
Set by hardware. These bits are the 8 LSB of the 11-bits Frame Number information.
• 7-5 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 4 - FNCERR -Frame Number CRC Error Flag
Set by hardware when a corrupted Frame Number in start of frame packet is received.
This bit and the SOFI interrupt are updated at the same time.
• 3-0 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 7-3 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 2-0 - EPNUM2:0 Endpoint Number Bits
Load by software to select the number of the endpoint which shall be accessed by the CPU. See
Section 22.5, page 267 for more details.
EPNUM = 111b is forbidden.
• 7 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 6-0 - EPRST6:0 - Endpoint FIFO Reset Bits
Set to reset the selected endpoint FIFO prior to any other operation, upon hardware reset or
when an USB bus reset has been received. See Section 22.3, page 266 for more information
Bit
Read/Write
Initial Value
Bit
Read/Write
Initial Value
Bit
Read/W
rite
Initial
Value
7
0
-
R
R
7
0
7
0
-
-
EPRST6
6
0
-
R/W
R
6
0
6
0
-
EPRST5
5
0
-
R/W
R
5
0
5
0
-
FNCERR
EPRST4
R
R/W
4
0
R
4
0
4
0
-
EPRST3
R/W
3
0
-
R
3
0
3
0
-
EPRST2
R/W
R/W
2
0
-
ATmega16/32U4
2
0
2
0
EPNUM2:0
EPRST1
R/W
R/W
1
0
-
1
0
1
0
EPRST0
R/W
R/W
0
0
-
0
0
0
0
UENUM
UDMFN
UERST
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