ATmega16U4 Atmel Corporation, ATmega16U4 Datasheet - Page 284

• 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

ATmega16/32U4
• 7 - CFGOK - Configuration Status Flag
Set by hardware when the endpoint X size parameter (EPSIZE) and the bank parametrization
(EPBK) are correct compared to the max FIFO capacity and the max number of allowed bank.
This bit is updated when the bit ALLOC is set.
If this bit is cleared, the user should reprogram the UECFG1X register with correct EPSIZE and
EPBK values.
• 6 - OVERFI - Overflow Error Interrupt Flag
Set by hardware when an overflow error occurs in an isochronous endpoint. An interrupt
(EPINTx) is triggered (if enabled).
See Section 22.15, page 275 for more details.
Shall be cleared by software. Setting by software has no effect.
• 5 - UNDERFI - Flow Error Interrupt Flag
Set by hardware when an underflow error occurs in an isochronous endpoint. An interrupt
(EPINTx) is triggered (if enabled).
See Section 22.15, page 275 for more details.
Shall be cleared by software. Setting by software has no effect.
• 4 - Reserved
The value read from these bits is always 0. Do not set these bits.
• 3-2 - DTSEQ1:0 - Data Toggle Sequencing Flag
Set by hardware to indicate the PID data of the current bank:
00b Data0
01b Data1
1xb
Reserved.
For OUT transfer, this value indicates the last data toggle received on the current bank.
For IN transfer, it indicates the Toggle that will be used for the next packet to be sent. This is not
relative to the current bank.
• 1-0 - NBUSYBK1:0 - Busy Bank Flag
Set by hardware to indicate the number of busy bank.
For IN endpoint, it indicates the number of busy bank(s), filled by the user, ready for IN transfer.
For OUT endpoint, it indicates the number of busy bank(s) filled by OUT transaction from the
host.
00b All banks are free
01b 1 busy bank
10b 2 busy banks
11b Reserved.
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