ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 5

• 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

4.3.2
4.3.2.1
Note:
4.4
7618C–AVR–07/08
Offset
Offset
15
16
17
0
1
2
3
4
5
6
7
8
1. Alternate settings can be used by an application to access additional memory segments. In this case, it is suggested that
Commands Description
DFU Configuration Descriptor
each alternate setting employ a string descriptor to indicate the target memory segment; e.g., “EEPROM”. Details concern-
ing other possible uses of alternate settings are beyond the scope of this document. However, their use is intentionally not
restricted because the authors anticipate that implements will devise additional creative uses for alternate settings.
DFU Interface Descriptor
bNumConfigurations
iSerialNumber
bInterfaceSubClass
bInterfaceProtocol
bInterfaceNumber
bAlternateSetting
iProduct
bDescriptorType
bNumEndpoints
bInterfaceClass
Field
iInterface
bLength
Field
This descriptor is identical to the standard configuration descriptor described in the USB DFU
specification version 1.0, with the exception that the bNumInterfaces field must contain the value
01h.
This is the descriptor for the only interface available when operating in DFU mode. Therefore,
the value of the bInterfaceNumber field is always zero.
Table 4-3.
The protocol implemented in the AT90USB bootloader allows to:
Overview of the protocol is detailed in
• Initiate the communication
• Program the Flash or EEPROM Data
• Read the Flash or EEPROM Data
• Program Configuration Information
• Read Configuration and Manufacturer Information
• Erase the Flash
• Start the application
Size
DFU Mode Interface Description
1
1
1
Size
1
1
1
1
1
1
1
1
1
Value
01h
0
0
Value
FEh
09h
04h
00h
00h
00h
01h
00h
00h
Index of string descriptor
Index of string descriptor
One configuration only for DFU
“Appendix-A” on page
Size of this descriptor, in bytes
INTERFACE descriptor type
Number of this interface
Alternate setting
Only the control pipe is used
Application Specific Class Code
Device Firmware Upgrade Code
The device does not use a class specific protocol on this interface
Index of the String descriptor for this interface
(1)
Description
18.
Description
5