SAM3U Datasheet, PDF (33/59 Pages) ATMEL Corporation – AT91SAM ARM-based Flash MCU

SAM3U Series
9.1.3.6
9.1.3.7
9.1.3.8
9.1.3.9
9.1.3.10
operation. However, it is safer to connect it directly to GND for the final application.
Calibration Bits
NVM bits are used to calibrate the brownout detector and the voltage regulator. These bits are
factory configured and cannot be changed by the user. The ERASE pin has no effect on the cal-
ibration bits.
Unique Identifier
Each device integrates its own 128-bit unique identifier. These bits are factory configured and
cannot be changed by the user. The ERASE pin has no effect on the unique identifier.
Fast Flash Programming Interface
The Fast Flash Programming Interface allows programming the device through either a serial
JTAG interface or through a multiplexed fully-handshaked parallel port. It allows gang program-
ming with market-standard industrial programmers.
The FFPI supports read, page program, page erase, full erase, lock, unlock and protect
commands.
The Fast Flash Programming Interface is enabled and the Fast Programming Mode is entered
when TST, NRSTB and FWUP pins are tied high during power up sequence and if all supplies
are provided externally (do not use internal regulator for VDDCORE). Please note that since the
FFPI is a part of the SAM-BA Boot Application, the device must boot from the ROM.
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.
GPNVM Bits
The SAM3U features three GPNVM bits that can be cleared or set respectively through the com-
mands “Clear GPNVM Bit” and “Set GPNVM Bit” of the EEFC User Interface.
The SAM3U4 is equipped with two EEFC, EEFC0 and EEFC1. EEFC1 does not feature the
GPNVM bits. The GPNVM embedded on EEFC0 applies to the two blocks in the SAM3U4.
Table 9-1. General-purpose Non-volatile Memory Bits
GPNVMBit[#]
Function
0
Security bit
1
Boot mode selection
2
Flash selection (Flash 0 or Flash 1) Only on SAM3U4 (256 Kbytes internal
Flash version)
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