AT25DF321A-SH-T Atmel, AT25DF321A-SH-T Datasheet - Page 19

• Manufacturer Part Number: AT25DF321A-SH-T
• Description: IC FLASH 32MBIT 100MHZ 8SOIC
• Manufacturer: Atmel

Specifications of AT25DF321A-SH-T

• Format - Memory: FLASH
• Memory Type: DataFLASH
• Memory Size: 32M (16384 pages x 256 Bytes)
• Speed: 100MHz
• Interface: SPI, RapidS
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOIC (5.3mm Width), 8-SOP, 8-SOEIAJ
• Density: 32Mb
• Access Time (max): 5ns
• Interface Type: Serial (SPI)
• Address Bus: 1b
• Operating Supply Voltage (typ): 3.3V
• Operating Temp Range: -40C to 85C
• Package Type: SOIC
• Program/erase Volt (typ): 2.7 to 3.6V
• Sync/async: Synchronous
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (min): 2.7V
• Operating Supply Voltage (max): 3.6V
• Word Size: 8b
• Number Of Words: 4M
• Supply Current: 19mA
• Mounting: Surface Mount
• Pin Count: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3686D–DFLASH–12/09
9.3
Figure 9-2.
Protect Sector
Every physical 64-Kbyte sector of the device has a corresponding single-bit Sector Protection Register that is used to
control the software protection of a sector. Upon device power-up, each Sector Protection Register will default to the
logical “1” state indicating that all sectors are protected and cannot be programmed or erased.
Issuing the Protect Sector command to a particular sector address will set the corresponding Sector Protection Register to
the logical “1” state. The following table outlines the two states of the Sector Protection Registers.
Table 9-1.
Before the Protect Sector command can be issued, the Write Enable command must have been previously issued to set
the WEL bit in the Status Register to a logical “1”. To issue the Protect Sector command, the CS pin must first be asserted
and the opcode of 36h must be clocked into the device followed by three address bytes designating any address within
the sector to be protected. Any additional data clocked into the device will be ignored. When the CS pin is deasserted, the
Sector Protection Register corresponding to the physical sector addressed by A23-A0 will be set to the logical “1” state,
and the sector itself will then be protected from program and erase operations. In addition, the WEL bit in the Status
Register will be reset back to the logical “0” state.
The complete three address bytes must be clocked into the device before the CS pin is deasserted, and the CS pin must
be deasserted on an even byte boundary (multiples of eight bits); otherwise, the device will abort the operation. When
the device aborts the Protect Sector operation, the state of the Sector Protection Register will be unchanged, and the WEL
bit in the Status Register will be reset to a logical “0”.
As a safeguard against accidental or erroneous protecting or unprotecting of sectors, the Sector Protection Registers can
themselves be locked from updates by using the SPRL (Sector Protection Registers Locked) bit of the Status Register
(please refer to the Status Register description for more details). If the Sector Protection Registers are locked, then any
attempts to issue the Protect Sector command will be ignored, and the device will reset the WEL bit in the Status Register
back to a logical “0” and return to the idle state once the CS pin has been deasserted.
SCK
Value
SO
CS
SI
0
1
Sector Protection Status
Sector is unprotected and can be programmed and erased
Sector is protected and cannot be programmed or erased. This is the default state
Write Disable
Sector Protection Register Values
HIGH-IMPEDANCE
MSB
0
0
0
1
0
2
OPCODE
0
3
0
4
1
5
0
6
0
7
Atmel AT25DF321A
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