M25PE10, M25PE20
Page Write (PW)
The Page Write (PW) instruction allows Bytes to
be written in the memory. Before it can be accept-
ed, a Write Enable (WREN) instruction must previ-
ously have been executed. After the Write Enable
(WREN) instruction has been decoded, the device
sets the Write Enable Latch (WEL).
The Page Write (PW) instruction is entered by
driving Chip Select (S) Low, followed by the in-
struction code, three address Bytes and at least
one data Byte on Serial Data Input (D). The rest of
the page remains unchanged if no power failure
occurs during this write cycle.
requested addresses without having any effects
on the other Bytes of the same page.
For optimized timings, it is recommended to use
the Page Write (PW) instruction to write all con-
secutive targeted Bytes in a single sequence ver-
sus using several Page Write (PW) sequences
with each containing only a few Bytes (see AC
Characteristics (33MHz operation)).
Chip Select (S) must be driven High after the
eighth bit of the last data Byte has been latched in,
otherwise the Page Write (PW) instruction is not
executed.
As soon as Chip Select (S) is driven High, the self-
The Page Write (PW) instruction performs a page
erase cycle even if only one Byte is updated.
timed Page Write cycle (whose duration is t ) is
PW
initiated. While the Page Write cycle is in progress,
the Status Register may be read to check the val-
ue of the Write In Progress (WIP) bit. The Write In
Progress (WIP) bit is 1 during the self-timed Page
Write cycle, and is 0 when it is completed. At some
unspecified time before the cycle is complete, the
Write Enable Latch (WEL) bit is reset.
If the 8 least significant address bits (A7-A0) are
not all zero, all transmitted data exceeding the ad-
dressed page boundary roll over, and are written
from the start address of the same page (the one
whose 8 least significant address bits (A7-A0) are
all zero). Chip Select (S) must be driven Low for
the entire duration of the sequence.
A Page Write (PW) instruction applied to a page
that is Hardware Protected is not executed.
The instruction sequence is shown in Figure 14.
Any Page Write (PW) instruction, while an Erase,
Program or Write cycle is in progress, is rejected
without having any effects on the cycle that is in
progress.
If more than 256 Bytes are sent to the device, pre-
viously latched data are discarded and the last 256
data Bytes are guaranteed to be written correctly
within the same page. If less than 256 Data Bytes
are sent to device, they are correctly written at the
Figure 14. Page Write (PW) Instruction Sequence
S
0
1
2
3
4
5
6
7
8
9
10
28 29 30 31 32 33 34 35 36 37 38 39
C
D
Instruction
24-Bit Address
Data Byte 1
23 22 21
MSB
3
2
1
0
7
6
5
4
3
2
0
1
MSB
S
C
40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55
Data Byte 2
Data Byte 3
Data Byte n
7
6
5
4
3
2
0
7
6
5
4
3
2
0
7
6
5
4
3
2
0
1
1
1
D
MSB
MSB
MSB
AI04045
Note: 1. Address bits A23 to A18 are Don’t Care in the M25PE20. Address bits A23 to A17 are Don’t Care in the M25PE10.
2. 1 ≤n ≤256
18/37
SST [ SILICON STORAGE TECHNOLOGY, INC ]
