18
ATmega165A/PA/325A/PA/3250A/PA/645A/P/6450A/P [DATASHEET]
8285E–AVR–02/2013
8.
AVR memories
This chapter describes the different memories in the Atmel
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P. The AVR architecture has two main
m e m o ry spa c es, the Dat a M e m o r y an d t he Prog ra m M e m o r y sp ace . In ad dition , th e
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P features an EEPROM Memory for
data storage. All three memory spaces are linear and regular.
8.1
In-System Reprogrammable Flash Program Memory
The ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P contains 16/32/64K bytes On-
chip In-System Reprogrammable Flash memory for program storage. Since all AVR instructions are 16 or 32 bits
wide, the Flash is organized as 8K x 16. For software security, the Flash Program memory space is divided into
two sections, Boot Program section and Application Program section.
The
Flas h
memory
has
an
en durance
of
at
least
10,000
write/erase
cycles.
The
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P Program Counter (PC) is 13/14/15
bits wide, thus addressing the 8/16/32K program memory locations. The operation of Boot Program section and
Flash data serial downloading using the SPI pins or the JTAG interface.
Constant tables can be allocated within the entire program memory address space (see the LPM – Load Program
Memory instruction description).
Figure 8-1.
Program memory map.
8.2
SRAM data memory
The ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/6450A/6450P is a complex microcontroller with
more peripheral units than can be supported within the 64 locations reserved in the Opcode for the IN and OUT
0x0000
0x1FFF/0x3FFF/0x7FFF
Program Memory
Application Flash Section
Boot Flash Section