M45PE20
INSTRUCTIONS
All instructions, addresses and data are shifted in
and out of the device, most significant bit first.
Serial Data Input (D) is sampled on the first rising
edge of Serial Clock (C) after Chip Select (S) is
driven Low. Then, the one-byte instruction code
must be shifted in to the device, most significant bit
first, on Serial Data Input (D), each bit being
latched on the rising edges of Serial Clock (C).
The instruction set is listed in Table 4..
Every instruction sequence starts with a one-byte
instruction code. Depending on the instruction,
this might be followed by address bytes, or by data
bytes, or by both or none.
In the case of a Read Data Bytes (READ), Read
Data Bytes at Higher Speed (Fast_Read) or Read
Status Register (RDSR) instruction, the shifted-in
instruction sequence is followed by a data-out se-
quence. Chip Select (S) can be driven High after
any bit of the data-out sequence is being shifted
out.
In the case of a Page Write (PW), Page Program
(PP), Page Erase (PE), Sector Erase (SE), Write
Enable (WREN), Write Disable (WRDI), Deep
Power-down (DP) or Release from Deep Power-
down (RDP) instruction, Chip Select (S) must be
driven High exactly at a byte boundary, otherwise
the instruction is rejected, and is not executed.
That is, Chip Select (S) must driven High when the
number of clock pulses after Chip Select (S) being
driven Low is an exact multiple of eight.
All attempts to access the memory array during a
Write cycle, Program cycle or Erase cycle are ig-
nored, and the internal Write cycle, Program cycle
or Erase cycle continues unaffected.
Table 4. Instruction Set
Instruction
Description
One-byte Instruction Code
WREN Write Enable
0000 0110
06h
WRDI
Write Disable
0000 0100
04h
RDID
Read Identification
1001 1111
9Fh
RDSR Read Status Register
0000 0101
05h
READ
Read Data Bytes
0000 0011
03h
FAST_READ Read Data Bytes at Higher Speed 0000 1011
0Bh
PW
Page Write
0000 1010
0Ah
PP
Page Program
0000 0010
02h
PE
Page Erase
1101 1011
DBh
SE
Sector Erase
1101 1000
D8h
DP
Deep Power-down
1011 1001
B9h
RDP
Release from Deep Power-down
1010 1011
ABh
Address
Bytes
0
0
0
0
3
3
3
3
3
3
0
0
Dummy
Bytes
0
0
0
0
0
1
0
0
0
0
0
0
Data
Bytes
0
0
1 to 3
1 to ∞
1 to ∞
1 to ∞
1 to 256
1 to 256
0
0
0
0
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