Datasheet

15
7728G–AVR–06/10
ATtiny87/ATtiny167
3. AVR Memories
This section describes the different memories in the ATtiny87/167. The AVR architecture has
two main memory spaces, the Data memory and the Program memory space. In addition, the
ATtiny87/167 features an EEPROM Memory for data storage. All three memory spaces are
linear and regular.
Notes: 1. Byte address.
2. Word (16-bit) address.
3.1 In-System Re-programmable Flash Program Memory
The ATtiny87/167 contains On-chip In-System Reprogrammable Flash memory for program
storage (see “Flash size” in Table 3-1 on page 15). Since all AVR instructions are 16 or 32 bits
wide, the Flash is organized as 16 bits wide. ATtiny87/167 does not have separate Boot
Loader and Application Program sections, and the SPM instruction can be executed from the
entire Flash. See SELFPRGEN description in Section 20.2.1 “Store Program Memory Control
and Status Register – SPMCSR” on page 219 for more details.
The Flash memory has an endurance of at least 10,000 write/erase cycles in automotive
range. The ATtiny87/167 Program Counter (PC) address the program memory locations. Sec-
tion 21. “Memory Programming” on page 225 contains a detailed description on Flash data
serial downloading using the SPI pins.
Constant tables can be allocated within the entire Program memory address space (see the
LPM – Load Program memory instruction description).
Table 3-1. Memory Mapping.
Memory Mnemonic ATtiny87 ATtiny167
Flash
Size Flash size 8 K bytes 16 K bytes
Start Address - 0x0000
End Address Flash end
0x1FFF
(1)
0x0FFF
(2)
0x3FFF
(1)
0x1FFF
(2)
32 Registers
Size - 32 bytes
Start Address - 0x0000
End Address - 0x001F
I/O
Registers
Size - 64 bytes
Start Address - 0x0020
End Address - 0x005F
Ext I/O
Registers
Size - 160 bytes
Start Address - 0x0060
End Address - 0x00FF
Internal
SRAM
Size ISRAM size 512 bytes
Start Address ISRAM start 0x0100
End Address ISRAM end 0x02FF
EEPROM
Size E2 size 512 bytes
Start Address - 0x0000
End Address E2 end 0x01FF