SAM3U Datasheet, PDF (34/59 Pages) ATMEL Corporation – AT91SAM ARM-based Flash MCU

9.1.4
Boot Strategies
The system always boots at address 0x0. To ensure a maximum boot possibilities the memory
layout can be changed via GPNVM.
A general purpose NVM (GPNVM1) bit is used to boot either on the ROM (default) or from the
Flash.
The 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 EEFC User Interface.
Setting the GPNVM Bit 1 selects the boot from the Flash, clearing it selects the boot from the
ROM. Asserting ERASE clears the GPNVM Bit 1 and thus selects the boot from the ROM by
default.
GPNVM2 enables to select if Flash 0 or Flash 1 is used for the boot. Setting the GPNVM2 bit
selects the boot from Flash 1, clearing it selects the boot from Flash 0.
9.2 External Memories
The SAM3U offers an interface to a wide range of external memories and to any parallel
peripheral.
9.2.1
Static Memory Controller
• 8- or 16- bit Data Bus
• Up to 24-bit Address Bus (up to 16 MBytes linear per chip select)
• Up to 4 chips selects, Configurable Assignment
• Multiple Access Modes supported
– Byte Write or Byte Select Lines
• Multiple device adaptability
– Control signals programmable setup, pulse and hold time for each Memory Bank
• Multiple Wait State Management
– Programmable Wait State Generation
– External Wait Request
– Programmable Data Float Time
• Slow Clock mode supported
9.2.2
9.2.3
NAND Flash Controller
• Handles automatic Read/Write transfer through 4224 bytes SRAM buffer
• DMA support
• Supports SLC NAND Flash technology
• Programmable timing on a per chip select basis
• Programmable Flash Data width 8-bit or 16-bit
NAND Flash Error Corrected Code Controller
• Integrated in the NAND Flash Controller
• Single bit error correction and 2-bit Random detection.
• Automatic Hamming Code Calculation while writing
– ECC value available in a register
• Automatic Hamming Code Calculation while reading
34 SAM3U Series
6430ES–ATARM–22-Aug-11