AT91SAM Datasheet, PDF (38/67 Pages) ATMEL Corporation – ARM-based Flash MCU

9.1.3.9
Fast Flash Programming Interface
The Fast Flash Programming Interface allows programming the device through a multiplexed
fully-handshaked parallel port. It allows gang programming with market-standard industrial
programmers.
The FFPI supports read, page program, page erase, full erase, lock, unlock and protect
commands.
9.1.3.10
SAM-BA Boot
The SAM-BA Boot is a default Boot Program which provides an easy way to program in-situ the
on-chip Flash memory.
The SAM-BA Boot Assistant supports serial communication via the UART and USB.
The SAM-BA Boot provides an interface with SAM-BA Graphic User Interface (GUI).
The SAM-BA Boot is in ROM and is mapped in Flash at address 0x0 when GPNVM bit 1 is set to 0.
9.1.3.11
GPNVM Bits
The SAM4S features two GPNVM bits. These bits can be cleared or set respectively through the
commands “Clear GPNVM Bit” and “Set GPNVM Bit” of the EEFC User Interface.
The Flash of the SAM4S16/SA16 is composed of 1024 Kbytes in a single bank. The Flash of the
SAM4S8 is composed of 512Kbytes in a single bank.
The SAM4SD32/SD16 features 3 GPNVM bits that can be cleared or set respectively through
the "Clear GPNVM Bit" and "Set GPNVM Bit" commands of the EEFC User Interface. The
GPNVM0 is the security bit. The GPNVM1 is used to select the boot mode (boot always at 0x00)
on ROM or FLASH. The SAM4SD32/16 embeds an additional GPNVM bit: GPNVM2. This
GPNVM bit is used only to swap the Flash0 and Flash1. If GPNVM bit 2 is:
ENABLE: the Flash1 is mapped at address 0x0040_0000 (Flash1 and Flash0 are continuous).
DISABLE: the Flash0 is mapped at address 0x0040_0000 (Flash0 and Flash1 are continuous).
Table 9-2. General-purpose Non volatile Memory Bits
GPNVMBit[#]
Function
0
Security bit
1
Boot mode selection
2
Flash selection (Flash 0 or Flash 1)
9.1.4
Boot Strategies
The system always boots at address 0x0. To ensure maximum boot possibilities, the memory
layout can be changed via GPNVM.
A general purpose NVM (GPNVM) 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 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.
38 SAM4S Series [Preliminary]
11100BS–ATARM–31-Jul-12