SAM7X256_14 Datasheet, PDF (22/662 Pages) ATMEL Corporation – ARM-based Flash MCU

 The GPNVM Bit 1 is used as a brownout reset enable signal for the reset controller. Setting the GPNVM Bit 1
enables the brownout reset when a brownout is detected, Clearing the GPNVM Bit 1 disables the brownout reset.
Asserting ERASE disables the brownout reset by default.
8.5.6
Calibration Bits
Eight 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 calibration bits.
8.6 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-programming 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 the TST pin and the
PA0 and PA1 pins are all tied high.
8.7 SAM-BA Boot Assistant
The SAM-BA Boot Assistant is a default Boot Program that provides an easy way to program in-situ the on-chip Flash
memory.
The SAM-BA Boot Assistant supports serial communication via the DBGU or the USB Device Port.
 Communication via the DBGU supports a wide range of crystals from 3 to 20 MHz via software auto-detection.
 Communication via the USB Device Port is limited to an 18.432 MHz crystal.
The SAM-BA Boot provides an interface with SAM-BA Graphic User Interface (GUI).
The SAM-BA Boot is in ROM and is mapped at address 0x0 when the GPNVM Bit 2 is set to 0.
When GPNVM bit 2 is set to 1, the device boots from the Flash.
When GPNVM bit 2 is set to 0, the device boots from ROM (SAM-BA).
SAM7X Series [DATASHEET] 22
6120K–ATARM–11-Feb-14