M95020-R datasheet(20/42 Pages) STMICROELECTRONICS

20 / 42 page

Instructions

M95040, M95020, M95010

20/42

6.4

Write Status Register (WRSR)

This instruction has no effect on bits b7, b6, b5, b4, b1 and b0 of the Status Register.

As shown in Figure 10, to send this instruction to the device, Chip Select (S) is first driven

low. The bits of the instruction byte and data byte are then shifted in on Serial Data Input

(D).

The instruction is terminated by driving Chip Select (S) high. Chip Select (S) must be driven

high after the rising edge of Serial Clock (C) that latches the eighth bit of the data byte, and

before the next rising edge of Serial Clock (C). If this condition is not met, the Write Status

continues for a period tW (as specified in Table 13 to Table 20), at the end of which the Write

in Progress (WIP) bit is reset to 0.

The instruction is not accepted, and is not executed, under the following conditions:

●

if the Write Enable Latch (WEL) bit has not been set to 1 (by executing a Write Enable

instruction just before)

●

if a Write Cycle is already in progress

●

if the device has not been deselected, by Chip Select (S) being driven high, after the

eighth bit, b0, of the data byte has been latched in

●

if Write Protect (W) is low.

Figure 10.

Write Status Register (WRSR) sequence

AI01445B

3456789 10 11 12 13 14 15

High Impedance

Instruction

Status

765432

MSB

M95020-R Datasheet(PDF) 20 Page - STMicroelectronics