ATmega16U2 Atmel Corporation, ATmega16U2 Datasheet - Page 230

• Manufacturer Part Number: ATmega16U2
• Manufacturer: Atmel Corporation

Specifications of ATmega16U2

• Flash (kbytes): 16 Kbytes
• Pin Count: 32
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 12
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 22
• Ext Interrupts: 21
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 2
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 0.5
• 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: 2
• Output Compare Channels: 5
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

23.6
23.6.1
23.6.2
7799D–AVR–11/10
Entering the Boot Loader Program
Regular application conditions.
Boot Reset Fuse
Table 23-2.
Note:
Table 23-3.
Note:
The bootloader can be executed with three different conditions:
A jump or call from the application program. This may be initiated by a trigger such as a com-
mand received via USART, or SPI interface.
The Boot Reset Fuse (BOOTRST) can be programmed so that the Reset Vector is pointing to
the Boot Flash start address after a reset. In this case, the Boot Loader is started after a reset.
After the application code is loaded, the program can start executing the application code. Note
that the fuses cannot be changed by the MCU itself. This means that once the Boot Reset Fuse
BLB0 Mode
BLB1 Mode
1
2
3
4
1
2
3
4
1. “1” means unprogrammed, “0” means programmed
1. “1” means unprogrammed, “0” means programmed
Boot Lock Bit0 Protection Modes (Application Section)
Boot Lock Bit1 Protection Modes (Boot Loader Section)
BLB02
BLB12
1
1
0
0
1
1
0
0
BLB01
BLB11
1
0
0
1
1
0
0
1
Protection
No restrictions for SPM or (E)LPM accessing the Application
section.
SPM is not allowed to write to the Application section.
SPM is not allowed to write to the Application section, and
(E)LPM executing from the Boot Loader section is not allowed
to read from the Application section. If Interrupt Vectors are
placed in the Boot Loader section, interrupts are disabled while
executing from the Application section.
(E)LPM executing from the Boot Loader section is not allowed
to read from the Application section. If Interrupt Vectors are
placed in the Boot Loader section, interrupts are disabled while
executing from the Application section.
Protection
No restrictions for SPM or (E)LPM accessing the Boot Loader
section.
SPM is not allowed to write to the Boot Loader section.
SPM is not allowed to write to the Boot Loader section, and
(E)LPM executing from the Application section is not allowed to
read from the Boot Loader section. If Interrupt Vectors are
placed in the Application section, interrupts are disabled while
executing from the Boot Loader section.
(E)LPM executing from the Application section is not allowed to
read from the Boot Loader section. If Interrupt Vectors are
placed in the Application section, interrupts are disabled while
executing from the Boot Loader section.
ATmega8U2/16U2/32U2
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