HN58X2508IAG Series, HN58X2516IAG Series

Write Disable (WRDI):

One way of resetting the Write Enable Latch (WEL) bit is to send a Write Disable instruction to the device. As shown

in the following figure, 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 the device to be deselected, by chip select (

S) being driven high. The

Write Enable Latch (WEL) bit, in fact, becomes reset by any of the following events:

 Power-up

 WRDI instruction execution

 WRSR instruction completion

 WRITE instruction completion

Write Disable (WRDI) Sequence

S

W

C

D

Q

Instruction

1

0

2

3

4

567

High-Z

V

IH

V

IL

V

IH

V

IL

V

IH

V

IL

V

IH

V

IL

Rev.1.00, Nov.08.2006, page 11 of 20