AT45DB321C-RI ATMEL [ATMEL Corporation], AT45DB321C-RI Datasheet - Page 10

• Manufacturer Part Number: AT45DB321C-RI
• Description: 32 MEGABIT 2.7 VOLT DATAFLASH
• Manufacturer: ATMEL [ATMEL Corporation]

10
AT45DB321C [Preliminary]
tialize the read operation. After the 32 don’t care clock cycles, any additional clock
pulses on the SCK pin will result in data being output on the SO (serial output) pin. The
read will begin with Byte_1 of the Sector Protection Register for Sector_0, followed with
Byte_2 for Sector_1. The read operation will continue until Byte_16 for Sector_15 is
read. Once the last byte is read a low-to-high transition on the CS pin is required to ter-
minate the read operation.
VARIOUS ASPECTS ABOUT THE SECTOR PROTECTION REGISTER: Due to the
sharing of the internal circuitry, the contents of the buffer 1 will get modified during the
erase and programming of Sector Protection Register. If the device is powered down
during erasing or programming the sector protection register, then the contents of the
Sector Protection Register cannot be guaranteed. The Sector Protection Register can
be erased or reprogrammed with the sector protection enabled or disabled. Being able
to reprogram the Sector Protection Register with the sector protection enabled allows
the user to temporarily disable the sector protection to an individual sector rather than
disabling the sector protection completely.
The Sector Protection Register is subject to the same endurance characteristics as the
main memory array. Users are encouraged to carefully evaluate the number of times the
Sector Protection Register will be modified during the course of the applications’ life
cycle. If the application requires that the Sector Protection Register be modified more
than the specified endurance of the DataFlash because the application needs to tempo-
rarily unprotect individual sectors (sector protection remains enabled while the Sector
Protection Register is reprogrammed), then the application will need to limit this prac-
tice. Instead, a combination of temporarily unprotecting individual sectors along with
disabling sector protection completely will need to be implemented by the application to
ensure that the endurance limits of the device are not exceeded.
Command
Read Sector Protection Register
Byte 1
32H
Byte 2
00H
Byte 3
00H
3387B–DFLSH–9/04
Byte 4
00H