at90pwm81-16se ATMEL Corporation, at90pwm81-16se Datasheet - Page 16

• Manufacturer Part Number: at90pwm81-16se
• Description: 8-bit Avr Microcontroller With 8k Bytes In- System Programmable Flash
• Manufacturer: ATMEL Corporation

5.
5.1
5.2
16
Memories
In-System Reprogrammable Flash Program Memory
SRAM Data Memory
AT90PWM81
This section describes the different memories in the AT90PWM81. The AVR architecture has two main
memory spaces, the Data Memory and the Program Memory space. In addition, the AT90PWM81 fea-
tures an EEPROM Memory for data storage. All three memory spaces are linear and regular.
The AT90PWM81 contains 8K 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 4K x 16. For software
security, the Flash Program memory space is divided into two sections, Boot Program section and Appli-
cation Program section.
The Flash memory has an endurance of at least 10,000 write/erase cycles. The AT90PWM81 Program
Counter (PC) is 12 bits wide, thus addressing the 4K program memory locations. The operation of Boot
Program section and associated Boot Lock bits for software protection are described in detail in
Loader Support – Read-While-Write Self-Programming” on page
247
Constant tables can be allocated within the entire program memory address space (see the LPM – Load
Program Memory.
Timing diagrams for instruction fetch and execution are presented in
page
Figure 5-1.
Figure 5-2
contains a detailed description on Flash programming in SPI or Parallel programming mode.
12.
shows how the AT90PWM81 SRAM Memory is organized.
Program Memory Map
Application Flash Section
Boot Flash Section
Program Memory
232.
“Instruction Execution Timing” on
“Memory Programming” on page
0x0000
0x0FFF
7734M–AVR–03/10
“Boot