atmega323l ATMEL Corporation, atmega323l Datasheet - Page 177

• Manufacturer Part Number: atmega323l
• Description: Atmega323 8-bit Avr Microcontroller With 32k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Memory
Programming
Boot Loader Support
1457G–AVR–09/03
The ATmega323 provides a mechanism for downloading and uploading program code
by the MCU itself. This feature allows flexible application software updates, controlled
by the MCU using a Flash-resident Boot Loader program. This makes it possible to pro-
gram the AVR in a target system without access to its SPI pins. The Boot Loader
program can use any available data interface and associated protocol, such as USART
serial bus interface, to input or output program code, and write (program) that code into
the Flash memory, or read the code from the Flash memory.
The ATmega323 Flash memory is organized in two main sections:
•
•
The Application Flash section and the Boot Loader Flash section have separate Boot
Lock bits. Thus the user can select different levels of protection for the two sections. The
Store Program memory (SPM) instruction can only be executed from the Boot Loader
Flash section.
The program Flash memory in ATmega323 is divided into 256 pages of 64 words each.
The Boot Loader Flash section is located at the high address space of the Flash, and
can be configured through the BOOTSZ Fuses as shown in Table 59.
Table 59. Boot Size Configuration
BOOTSZ1
The Application Flash section
The Boot Loader Flash section
1
1
0
0
BOOTSZ0
1
0
1
0
256
words
512
words
1024
words
2048
words
Boot
Size
Pages
16
32
4
8
Flash Addresses
$0000 - $3EFF
$0000 - $3DFF
$0000 - $3BFF
$0000 - $37FF
Application
ATmega323(L)
Boot Flash
$3F00 -
$3FFF
$3E00 -
$3FFF
$3C00 -
$3FFF
$3800 -
$3FFF
Addresses
Boot Reset
Address
$3F00
$3E00
$3C00
$3800
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