Rainbow Electronics AT45DB321D - Manual (Page 25)

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3597J–DFLASH–4/08
AT45DB321D
13. “Power of 2” Binary Page Size Option
“Power of 2” binary page size Configuration Register is a user-programmable nonvolatile regis-
ter that allows the page size of the main memory to be configured for binary page size
(512 bytes) or DataFlash standard page size (528 bytes). The “power of 2” page size is a one-
time programmable configuration register and once the device is configured for “power
of 2” page size, it cannot be reconfigured again. The devices are initially shipped with the
page size set to 528 bytes. The user has the option of ordering binary page size (512
bytes) devices from the factory. For details, please refer to
Section 26. ”Ordering Information” on
page 47 .
For the binary “power of 2” page size to become effective, the following steps must be followed:
1. Program the one-time programmable configuration resister using opcode sequence
3DH, 2AH, 80H and A6H (please see
Section 13.1 ).
2. Power cycle the device (i.e. power down and power up again).
3. The page for the binary page size can now be programmed.
If the above steps are not followed to set the page size prior to page programming, incorrect
data during a read operation may be encountered.
13.1 Programming the Configuration Register
To program the Configuration Register for “power of 2” binary page size, the CS pin must first be
asserted as it would be with any other command. Once the CS pin has been asserted, the
appropriate 4-byte opcode sequence must be clocked into the device in the correct order. The
4-byte opcode sequence must start with 3DH and be followed by 2AH, 80H, and A6H. After the
last bit of the opcode sequence has been clocked in, the CS pin must be deasserted to initiate
the internally self-timed program cycle. The programming of the Configuration Register should
take place in a time of t
P
, during which time the Status Register will indicate that the device is
busy. The device must be power cycled after the completion of the program cycle to set the
“power of 2” page size. If the device is powered-down before the completion of the program
cycle, then setting the Configuration Register cannot be guaranteed. However, the user should
check bit 0 of the status register to see whether the page size was configured for binary page
size. If not, the command can be re-issued again.
Figure 13-1. Erase Sector Protection Register
Command Byte 1 Byte 2 Byte 3 Byte 4
Power of Two Page Size 3DH 2AH 80H A6H
Opcode
Byte 1
Opcode
Byte 2
Opcode
Byte 3
Opcode
Byte 4
CS
Each transition
represents 8 bits
SI