AT91SAM7X256-AU(2006_02) データシートの表示（PDF） - Atmel Corporation

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AT91SAM7X256-AU
(Rev.:2006_02)

AT91 ARM® Thumb®-based Microcontrollers

Atmel Corporation 

9.3 Memory Mapping

9.3.1

Internal RAM

• The AT91SAM7X256 embeds a high-speed 64-Kbyte SRAM bank

• The AT91SAM7X128 embeds a high-speed 32-Kbyte SRAM bank.

After reset and until the Remap Command is performed, the SRAM is only accessible at address

0x0020 0000. After Remap, the SRAM also becomes available at address 0x0.

9.3.2

Internal ROM

The AT91SAM7X256/128 embeds an Internal ROM. At any time, the ROM is mapped at

address 0x30 0000. The ROM contains FFPI and SAM-BA program.

9.3.3

Internal Flash

• The AT91SAM7X256 features one bank of 256 Kbytes of Flash

• The AT91SAM7X128 features one bank of 128 Kbytes of Flash.

At any time, the Flash is mapped to address 0x0010 0000. It is also accessible at address 0x0

after the reset and before the Remap Command.

A general purpose NVM (GPNVM) bit is used to boot either on the ROM (default) or from the

Flash.

This GPNVM bit can be cleared or set respectively through the commands “Clear General-pur-

pose NVM Bit” and “Set General-purpose NVM Bit” of the EFC User Interface.

Setting the GPNVM Bit 2 selects the boot from the Flash. Asserting ERASE clears the GPNVM

Bit 2 and thus selects the boot from the ROM by default.

Figure 9-1. Internal Memory Mapping with GPNVM Bit 2 = 0 (default)

0x0000 0000

0x000F FFFF

0x0010 0000

256M Bytes

0x001F FFFF

0x0020 0000

0x002F FFFF

0x0030 0000

0x003F FFFF

0x0040 0000

ROM Before Remap

SRAM After Remap

Internal FLASH

Internal SRAM

Internal ROM

Undefined Areas

(Abort)

1 M Bytes

1 M Bytes

1 M Bytes

1 M Bytes

252 M Bytes

0x0FFF FFFF

16 AT91SAM7X256/128 Preliminary

6120D–ATARM–02-Feb-06

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