M95320, M95640, M95320-x, M95640-x
Instructions
6
Instructions
Each instruction starts with a single-byte code, as summarized in Table 3.
If an invalid instruction is sent (one not contained in <Blue>Table 3.), the device
automatically deselects itself.
Table 3.
Instruction set
Instruction
Description
Instruction Format
WREN
WRDI
Write Enable
0000 0110
0000 0100
0000 0101
0000 0001
0000 0011
0000 0010
Write Disable
RDSR
WRSR
READ
WRITE
Read Status Register
Write Status Register
Read from Memory Array
Write to Memory Array
6.1
Write Enable (WREN)
The Write Enable Latch (WEL) bit must be set prior to each WRITE and WRSR instruction.
The only way to do this is to send a Write Enable instruction to the device.
As shown in Figure 7, to send this instruction to the device, Chip Select (S) is driven Low,
and the bits of the instruction byte are shifted in, on Serial Data Input (D). The device then
enters a wait state. It waits for a the device to be deselected, by Chip Select (S) being driven
High.
Figure 7.
Write Enable (WREN) sequence
S
0
1
2
3
4
5
6
7
C
D
Q
Instruction
High Impedance
AI02281E
15/44
STMICROELECTRONICS [ ST ]
