AT25DF641A datasheet(36/57 Pages) ATMEL

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8693A–DFLASH–8/10

Atmel AT25DF641A [Preliminary]

11.1.2

EPE Bit

The EPE bit indicates whether the last erase or program operation completed successfully or

not. If at least one byte during the erase or program operation did not erase or program properly,

then the EPE bit will be set to the logical “1” state. The EPE bit will not be set if an erase or pro-

gram operation aborts for any reason such as an attempt to erase or program a protected region

or a locked down sector, an attempt to erase or program a suspended sector, or if the WEL bit is

not set prior to an erase or program operation. The EPE bit will be updated after every erase and

program operation.

11.1.3

WPP Bit

The WPP bit can be read to determine if the WP pin has been asserted or not.

11.1.4

SWP Bits

The SWP bits provide feedback on the software protection status for the device. There are three

possible combinations of the SWP bits that indicate whether none, some, or all of the sectors

have been protected using the Protect Sector command or the Global Protect feature. If the

SWP bits indicate that some of the sectors have been protected, then the individual Sector Pro-

tection Registers can be read with the Read Sector Protection Registers command to determine

which sectors are in fact protected.

11.1.5

WEL Bit

The WEL bit indicates the current status of the internal Write Enable Latch. When the WEL bit is

in the logical “0” state, the device will not accept any Byte/Page Program, erase, Protect Sector,

Unprotect Sector, Sector Lockdown, Freeze Sector Lockdown State, Program OTP Security

a device power-up or reset operation. In addition, the WEL bit will be reset to the logical “0” state

automatically under the following conditions:

• Write Disable operation completes successfully

• Write Status Register operation completes successfully or aborts

• Protect Sector operation completes successfully or aborts

• Unprotect Sector operation completes successfully or aborts

• Sector Lockdown operation completes successfully or aborts

• Freeze Sector Lockdown State operation completes successfully or aborts

• Program OTP Security Register operation completes successfully or aborts

• Byte/Page Program operation completes successfully or aborts

• Block Erase operation completes successfully or aborts

• Chip Erase operation completes successfully or aborts

• Hold condition aborts

If the WEL bit is in the logical “1” state, it will not be reset to a logical “0” if an operation aborts

due to an incomplete or unrecognized opcode being clocked into the device before the CS pin is

deasserted. In order for the WEL bit to be reset when an operation aborts prematurely, the entire

opcode for a Byte/Page Program, erase, Protect Sector, Unprotect Sector, Sector Lockdown,

Freeze Sector Lockdown State, Program OTP Security Register, or Write Status Register com-

mand must have been clocked into the device.

AT25DF641A Datasheet(PDF) 36 Page - ATMEL Corporation

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