AT25BCM512B Datasheet, PDF (9/33 Pages) List of Unclassifed Manufacturers – 512-Kilobit 2.7-Volt Minimum SPI Serial Flash Memory

AT25BCM512B [Preliminary]
Figure 8-1. Byte Program
CS
SCK
SI
SO
0 1 2 3 4 5 6 7 8 9 10 11 12
29 30 31 32 33 34 35 36 37 38 39
OPCODE
ADDRESS BITS A23-A0
DATA IN
0 0 0 0 0 0 1 0AAAAAA
MSB
MSB
AAADDDDDDDD
MSB
HIGH-IMPEDANCE
Figure 8-2. Page Program
CS
SCK
SI
SO
0123456789
29 30 31 32 33 34 35 36 37 38 39
OPCODE
ADDRESS BITS A23-A0
DATA IN BYTE 1
0 0 0 0 0 0 1 0AAA
MSB
MSB
AAADDDDDDDD
MSB
HIGH-IMPEDANCE
DATA IN BYTE n
DDDDDDDD
MSB
8.2 Block Erase
A block of 4 or 32 Kbytes can be erased (all bits set to the logical “1” state) in a single operation
by using one of three different opcodes for the Block Erase command. An opcode of 20h is used
for a 4-Kbyte erase, and an opcode of 52h or D8h is used for a 32-Kbyte erase. Before a Block
Erase command can be started, the Write Enable command must have been previously issued
to the device to set the WEL bit of the Status Register to a logical “1” state.
To perform a Block Erase, the CS pin must first be asserted and the appropriate opcode (20h,
52h, or D8h) must be clocked into the device. After the opcode has been clocked in, the three
address bytes specifying an address within the 4- or 32-Kbyte block to be erased must be
clocked in. Any additional data clocked into the device will be ignored. When the CS pin is deas-
serted, the device will erase the appropriate block. The erasing of the block is internally self-
timed and should take place in a time of t_BLKE.
Since the Block Erase command erases a region of bytes, the lower order address bits do not
need to be decoded by the device. Therefore, for a 4-Kbyte erase, address bits A11-A0 will be
ignored by the device and their values can be either a logical “1” or “0”. For a 32-Kbyte erase,
address bits A14-A0 will be ignored by the device. Despite the lower order address bits not
being decoded by the device, the complete three address bytes must still 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 and no erase
operation will be performed.
If the memory is in the protected state, then the Block Erase command will not be executed, and
the device will return to the idle state once the CS pin has been deasserted.
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3704BX–DFLASH–11/2012