ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 2

• Manufacturer Part Number: ATmega32U4
• Manufacturer: Atmel Corporation

Specifications of ATmega32U4

• Flash (kbytes): 32 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): 3.3
• Eeprom (bytes): 1024
• 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

2. Bootloader Environment
3. Bootloader Activation
2
The bootloader is located in the boot section of the on-chip Flash memory, it manages the USB
communication protocol and performs read/write operations to the on-chip memories
(Flash/EEPROM).
The USB bootloader is loaded in the “Bootloader Flash Section” of the on-chip Flash memory.
The size of the bootloader flash section must be larger than the bootloader size.USB products
are factory configured with the default on-chip USB bootloader and the required bootsection
configuration.
Table 2-1.
Figure 2-1.
As specified in the AT90USB datasheet, the bootloader can be activated by one of the following
conditions:
• Regular application execution: A jump or call from the user application program. This may
be initiated by a trigger such as a command received via USB, USART or SPI and decoded
by the application.
AT90USB1287
AT90USB1286
AT90USB647
AT90USB646
AT90USB162
ATmega32U4
ATmega16U4
AT90USB82
Product
USB Bootloader Parameters
Physical Environment
Flash Bootsection Size
Configuration
4 KWord
2 KWord
DFU Class
0x03EB / 0x2FFB
0x03EB / 0x2FF9
0x03EB / 0x2FFA
0x03EB / 0x2FF7
0x03EB / 0x2FF4
0x03EB / 0x2FF3
VID / PID
USB Bootloader
Interface
in Boot section
USB
Bootloader Start Address
Read/Write
Read/Write
(word address)
0x7800
0x1800
0x0800
0x3800
0x0800
0xf000
Application section
EEPROM Data
7618C–AVR–07/08
Flash