ATTINY20 データシートの表示（PDF） - Atmel Corporation

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ATTINY20

8-bit AVR Microcontroller with 2K Bytes In-System Programmable Flash

Atmel Corporation 

5. Memories

This section describes the different memories in the ATtiny20. The device has two main memory areas, the program

memory space and the data memory space.

5.1 In-System Re-programmable Flash Program Memory

The ATtiny20 contains 2K byte 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 1024 x 16.

The Flash memory has an endurance of at least 10,000 write/erase cycles. The ATtiny20 Program Counter (PC) is 10

bits wide, thus capable of addressing the 1024 program memory locations, starting at 0x000. “Memory Programming” on

page 159 contains a detailed description on Flash data serial downloading.

Constant tables can be allocated within the entire address space of program memory. Since program memory can not be

accessed directly, it has been mapped to the data memory. The mapped program memory begins at byte address

0x4000 in data memory (see Figure 5-1 on page 15). Although programs are executed starting from address 0x000 in

program memory it must be addressed starting from 0x4000 when accessed via the data memory.

Internal write operations to Flash program memory have been disabled and program memory therefore appears to

firmware as read-only. Flash memory can still be written to externally but internal write operations to the program

memory area will not be successful.

Timing diagrams of instruction fetch and execution are presented in “Instruction Execution Timing” on page 11.

5.2 Data Memory

Data memory locations include the I/O memory, the internal SRAM memory, the non-volatile memory lock bits, and the

Flash memory. See Figure 5-1 for an illustration on how the ATtiny20 memory space is organized.

Figure 5-1. Data Memory Map (Byte Addressing)

I/O SPACE

0x0000 ... 0x003F

SRAM DATA MEMORY

0x0040 ... 0x00BF

(reserved)

0x00C0 ... 0x3EFF

NVM LOCK BITS

0x3F00 ... 0x3F01

(reserved)

0x3F02 ... 0x3F3F

CONFIGURATION BITS 0x3F40 ... 0x3F41

(reserved)

0x3F42 ... 0x3F7F

CALIBRATION BITS

0x3F80 ... 0x3F81

(reserved)

0x3F82 ... 0x3FBF

DEVICE ID BITS

0x3FC0 ... 0x3FC3

(reserved)

0x3FC4 ... 0x3FFF

FLASH PROGRAM MEMORY 0x4000 ... 0x47FF

(reserved)

0x4800 ... 0xFFFF

ATtiny20 [DATASHEET] 15

Atmel-8235F-AVR-ATtiny20-Datasheet_09/2014

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