ATXMEGA256A3B-MH Atmel, ATXMEGA256A3B-MH Datasheet - Page 367

• Manufacturer Part Number: ATXMEGA256A3B-MH
• Description: MCU AVR 256KB FLASH A3B 64-QFN
• Manufacturer: Atmel
• Series: AVR® XMEGAr

Specifications of ATXMEGA256A3B-MH

• Core Processor: AVR
• Core Size: 8/16-Bit
• Speed: 32MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 49
• Program Memory Size: 256KB (128K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 4K x 8
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 1.6 V ~ 3.6 V
• Data Converters: A/D 16x12b; D/A 2x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-MLF®, 64-QFN
• Processor Series: ATXMEGA256x
• Core: AVR8
• Data Bus Width: 8 bit, 16 bit
• Data Ram Size: 16 KB
• Interface Type: I2C, SPI, USART
• Maximum Clock Frequency: 32 MHz
• Number Of Programmable I/os: 49
• Number Of Timers: 7
• Operating Supply Voltage: 1.6 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 12 bit, 8 Channel
• On-chip Dac: 12 bit, 2 Channel
• For Use With: ATAVRONEKIT - KIT AVR/AVR32 DEBUGGER/PROGRMMRATSTK600 - DEV KIT FOR AVR/AVR32770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATXMEGA256A3B-MU; ATXMEGA256A3B-MU

30.11 Self-Programming and Boot Loader Support
30.11.1
30.11.1.1
Table 30-1.
8077H–AVR–12/09
Section being addressed by Z-pointer
during the programming?
Application Section (RWW)
Boot Loader Section (NRWW)
User Signature Row section (NRWW)
Flash Programming
Application and Boot Loader sections
Summary of RWW and NRWW functionality
Both the EEPROM and the Flash memory can be read and written from the application software
in the device. This is referred to as self-programming. A Boot Loader (Application code located
in the Boot Loader Section of the Flash) can both read and write the Flash Program Memory,
User Signature Row and EEPROM, and write the Lock Bits to a more secure setting. Application
code in both the Application Section can read from the Flash, User Signature Row, Calibration
Row and Fuses, and read and write the EEPROM.
The Boot Loader support provides a real Read-While-Write self-programming mechanism for
downloading and uploading program code by the device itself. This feature allows flexible appli-
cation software updates controlled by the device using a Boot Loader application that reside in
the Boot Loader Section in the Flash. The Boot Loader can use any available communication
interface and associated protocol to read code and write (program) that code into the Flash
memory, or read out the program memory code. It has the capability to write into the entire
Flash, including the Boot Loader Section. The Boot Loader can thus modify itself, and it can also
erase itself from the code if the feature is not needed anymore.
The Application and Boot Loader sections are different when it comes to self-programming. The
Application Section is Read-While-Write (RWW) while the Boot Loader Section is No Read-
While-Write (NRWW). Here “Read-While-Write” refers to the section being programmed (erased
or written), not the section being read during a Boot Loader software update. Whether the CPU
can continue to run and execute code or is halted to stop program execution during a Boot
Loader software update is depending on the Flash address being programmed:
The User Signature Row section is NRWW, hence erasing or writing this section has the same
properties as for the Boot Loader Section.
During an on-going programming, the software must ensure that the Application Section is not
accessed. Doing this will halt the program execution from the CPU. The user software can not
read data located in the Application Section during a Boot Loader software operation.
• When erasing or writing a page located inside the Application Section (RWW), the Boot
• When erasing or writing a page located inside the Boot Loader Section (NRWW), the CPU is
Loader Section (NRWW) can be read during the operation, thus the CPU can run and
execute code from the Boot Loader Section (NRWW).
halted during the entire operation and code cannot execute.
Section that can be read during
programming
Boot Loader Section (NRWW)
None
None
CPU Halted
No
Yes
Yes
Read-While-Write
Supported
Yes
No
No
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