ATxmega256A3U Atmel Corporation, ATxmega256A3U Datasheet - Page 21

• Manufacturer Part Number: ATxmega256A3U
• Manufacturer: Atmel Corporation

Specifications of ATxmega256A3U

• Flash (kbytes): 256 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 32 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 50
• Ext Interrupts: 50
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 10
• Twi (i2c): 2
• Uart: 7
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 16
• Adc Resolution (bits): 12
• Adc Speed (ksps): 2000
• Analog Comparators: 4
• Resistive Touch Screen: No
• Dac Channels: 2
• Dac Resolution (bits): 12
• Temp. Sensor: Yes
• Crypto Engine: AES/DES
• Sram (kbytes): 16
• Eeprom (bytes): 4096
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.6 to 3.6
• Operating Voltage (vcc): 1.6 to 3.6
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 7
• Output Compare Channels: 22
• Input Capture Channels: 22
• Pwm Channels: 22
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

4.3.1
4.3.2
4.3.3
4.3.4
4.3.5
4.4
8331A–AVR–07/11
Fuses and Lockbits
Application Section
Application Table Section
Boot Loader Section
Production Signature Row
User Signature Row
The Application section is the section of the flash that is used for storing the executable applica-
tion code. The protection level for the application section can be selected by the boot lock bits
for this section. The application section can not store any boot loader code since the SPM
instruction cannot be executed from the application section.
The application table section is a part of the application section of the flash memory that can be
used for storing data. The size is identical to the boot loader section. The protection level for the
application table section can be selected by the boot lock bits for this section. The possibilities
for different protection levels on the application section and the application table section enable
safe parameter storage in the program memory. If this section is not used for data, application
code can reside here.
While the application section is used for storing the application code, the boot loader software
must be located in the boot loader section because the SPM instruction can initiate program-
ming when executing from this section. The SPM instruction can access the entire flash,
including the boot loader section itself. The protection level for the boot loader section can be
selected by the boot loader lock bits. If this section is not used for boot loader software, applica-
tion code can be stored here.
The production signature row is a separate memory section for factory programmed data. It con-
tains calibration data for functions such as oscillators and analog modules. Some of the
calibration values will be automatically loaded to the corresponding module or peripheral unit
during reset. Other values must be loaded from the signature row and written to the correspond-
ing peripheral registers from software. For details on calibration conditions such as temperature,
voltage references, etc. refer to device datasheet.
The production signature row also contains an ID that identifies each microcontroller device type
and a serial number for each manufactured device. The serial number consists of the production
lot number, wafer number, and wafer coordinates for the device.
The production signature row cannot be written or erased, but it can be read from application
software and external programmers.
The user signature row is a separate memory section that is fully accessible (read and write)
from application software and external programmers. It is one flash page in size, and is meant
for static user parameter storage, such as calibration data, custom serial number, identification
numbers, random number seeds, etc. This section is not erased by chip erase commands that
erase the flash, and requires a dedicated erase command. This ensures parameter storage dur-
ing multiple program/erase operations and on-chip debug sessions.
The fuses are used to configure important system functions, and can only be written from an
external programmer. The application software can read the fuses. The fuses are used to config-
ure reset sources such as brownout detector and watchdog, startup configuration, JTAG enable,
and JTAG user ID.
Atmel AVR XMEGA AU
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