Rainbow Electronics AT45DB161D - Manual (Page 22)

22
3500O–DFLASH–11/2012
AT45DB161D
Figure 12-2. Resume from Deep Power-Down
13. “Power of 2” Binary Page Size Option
“Power of 2” binary page size Configuration Register is a user-programmable nonvolatile register that allows the
page size of the main memory to be configured for binary page size (512-bytes) or standard DataFlash 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 44 .
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. User can now program the page for the binary page size.
If the above steps are not followed in setting the the page size prior to page programming, user may expect
incorrect data during a read operation.
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 zero 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.
Table 13-1. Programming the Configuration Register
Figure 13-1. Erase Sector Protection Register
Opcode
CS
Each transition
represents eight bits
SI
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 eight bits
SI