ATmega16U2 Atmel Corporation, ATmega16U2 Datasheet - Page 65

• 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

11.2.1
11.3
11.3.1
7799D–AVR–11/10
Register Description
Moving Interrupts Between Application and Boot Space
MCUCR – MCU Control Register
Table 11-1.
Notes:
Table 11-2
BOOTRST and IVSEL settings. If the program never enables an interrupt source, the Interrupt
Vectors are not used, and regular program code can be placed at these locations. This is also
the case if the Reset Vector is in the Application section while the Interrupt Vectors are in the
Boot section or vice versa.
Table 11-2.
Note:
The General Interrupt Control Register controls the placement of the Interrupt Vector table.
• Bit 1 – IVSEL: Interrupt Vector Select
When the IVSEL bit is cleared (zero), the Interrupt Vectors are placed at the start of the Flash
memory. When this bit is set (one), the Interrupt Vectors are moved to the beginning of the Boot
Loader section of the Flash. The actual address of the start of the Boot Flash Section is deter-
mined by the BOOTSZ Fuses. Refer to the section
details. To avoid unintentional changes of Interrupt Vector tables, a special write procedure must
be followed to change the IVSEL bit:
Bit
0x35 (0x55)
Read/Write
Initial Value
Vector
BOOTRST
No.
27
28
29
1
1
0
0
1. When the BOOTRST Fuse is programmed, the device will jump to the Boot Loader address at
2. When the IVSEL bit in MCUCR is set, Interrupt Vectors will be moved to the start of the Boot
1. The Boot Reset Address is shown in
reset, see
Flash Section. The address of each Interrupt Vector will then be the address in this table
added to the start address of the Boot Flash Section. Moreover, contrary to other 8K/16K
devices, the interrupt vectors spacing remains identical (2 words) for both 8KB and 16KB
versions.
means unprogrammed while “0” means programmed.
Address
shows reset and Interrupt Vectors placement for the various combinations of
Program
$0034
$0036
$0038
Reset and Interrupt Vectors (Continued)
Reset and Interrupt Vectors Placement
JTD
R/W
7
0
IVSEL
(2)
“Memory Programming” on page
0
1
0
1
Source
ANALOG COMP
EE READY
SPM READY
R
6
–
0
Reset Address
0x0000
0x0000
Boot Reset Address
Boot Reset Address
R
5
–
0
PUD
R/W
Table 23-8 on page
4
0
Interrupt Definition
Analog Comparator
EEPROM Ready
Store Program Memory Ready
ATmega8U2/16U2/32U2
246.
(1)
“Memory Programming” on page 246
R
3
–
0
Interrupt Vectors Start Address
0x0002
Boot Reset Address + 0x0002
0x0002
Boot Reset Address + 0x0002
R
239. For the BOOTRST Fuse “1”
2
–
0
IVSEL
R/W
1
0
IVCE
R/W
0
0
MCUCR
for
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