ATmega16U4 Atmel Corporation, ATmega16U4 Datasheet - Page 10

• Manufacturer Part Number: ATmega16U4
• Manufacturer: Atmel Corporation

Specifications of ATmega16U4

• Flash (kbytes): 16 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): 2.1
• 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: 4
• Output Compare Channels: 12
• Input Capture Channels: 2
• Pwm Channels: 8
• 32khz Rtc: No
• Calibrated Rc Oscillator: Yes

4.6.1.4
4.7
10
Reading the Flash or EEPROM Data
Answers from Bootloader
SETUP
OUT
OUT
OUT
OUT
IN
Figure 4-1.
The Host sends a DFU_DNLOAD request with Zero Length Packet (ZLP) to indicate that it has
completed transferring the firmware image file. This is the final payload packet of a download
operation.
After each program request, the Host can request the device state and status by sending a
DFU_GETSTATUS message.
If the device status indicates an error, the host must send a DFU_CLRSTATUS request to the
device.
The flow described below allows the user to read data in the Flash memory or in the EEPROM
data memory. A blank check command on the Flash memory is possible with this flow.
This operation is performed in 2 steps:
• DFU_DNLOAD request with the read command (6 bytes)
• DFU_UPLOAD request which correspond to the previous command.
Example of Firmware Download Zero Length DFU_DNLOAD Request
DFU_DNLOAD
Prog_Start + (EP0 fifo length - 6) x 00h
X offset bytes + Firmware Packet 1
Firmware Packet 2
Firmware Packet n + DFU suffix
ZLP
7618C–AVR–07/08