AT91SAM7S256 ATMEL Corporation, AT91SAM7S256 Datasheet - Page 15

• Manufacturer Part Number: AT91SAM7S256
• Description: AT91 ARM THUMB-BASED MICROCONTROLLERS
• Manufacturer: ATMEL Corporation

Non-volatile Brownout
Detector Control
Calibration Bits
Fast Flash Programming
Interface
6117AS–ATARM–20-Oct-04
Two general purpose NVM (GPNVM) bits are used for controlling the brownout detector
(BOD), so that even after a power loss, the brownout detector operations remain in their
state.
These two GPNVM bits can be cleared or set respectively through the commands
"Clear General-purpose NVM Bit" and "Set General-purpose NVM Bit" of the EFC User
Interface.
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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.
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.
The Flash of the AT91SAM7S256 is organized in 1024 pages of 256 bytes. It reads as
65,536 32-bit words.
The Flash contains a 256-byte write buffer, accessible through a 32-bit interface.
GPNVM Bit 0 is used as a brownout detector enable bit. Setting the GPNVM Bit 0
enables the BOD, clearing it disables the BOD. Asserting ERASE clears the
GPNVM Bit 0 and thus disables the brownout detector by default.
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.
AT91SAM7S256 Summary Preliminary
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