ATmega32U4 Atmel Corporation, ATmega32U4 Datasheet - Page 13

• 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

4.9
4.9.1
4.9.2
4.10
7618C–AVR–07/08
Erasing the Flash
Starting the Application
Request from Host
Answers from Bootloader
The flow described below allows the user to erase the Flash memory.
The Full Chip erase command erases the whole Flash.
To start the erasing operation, the Host sends a DFU_DNLOAD request with a Write Command
in the data field (2 bytes).
The device has two possible answers to a DFU_GETSTATUS request:
The flow described below allows to start the application directly from the bootloader upon a spe-
cific command reception.
Two options are possible:
•
•
To start the application, the Host sends a DFU_DNLOAD request with the specified application
start type in the data field (3 or 5 bytes).
This request is immediately followed by a second DFU_DNLOAD request with no data field to
start the application with one of the 2 options.
Command Identifier
• If the chip is protected from program access, an “err_WRITE” status is returned to the Host.
• Otherwise, the device status is “OK“.
Id_write_command
Start the application with an internal hardware reset using watchdog.
When the device receives this command the watchdog is enabled and the bootloader enters
a waiting loop until the watchdog resets the device.
Start the application without reset.
A jump at the address 0000h is used to start the application without reset.
04h
data[0]
00h
SETUP
IN
OUT
data[1]
FFh
data[2]
Byte value (1 byte)
DFU_UPLOAD
ZLP
data[3]
data[4]
Full chip Erase (bits at FFh)
Description
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