10

P/N:PM0823

REV. 0.5, JAN. 29, 2002

MX26L6420

SOFTWARE COMMAND DEFINTIONS

Device operations are selected by writing specific ad-

dress and data sequences into the command register.

Writing incorrect address and data values or writing them

in the improper sequence will reset the device to the

read mode. Table 4 defines the valid register command

sequences. Either of the two reset command sequences

Legend:

X=Don't care

RA=Address of the memory location to be read.

RD=Data read from location RA during read operation.

PA=Address of the memory location to be programmed.

Addresses are latched on the falling edge of the WE or

CE pulse.

PD=Data to be programmed at location PA. Data is

latched on the rising edge of WE or CE pulse.

will reset the device(when applicable).

All addresses are latched on the falling edge of WE or

CE, whichever happens later. All data are latched on ris-

ing edge of WE or CE, whichever happens first.

First Bus

Second Bus Third Bus

Fourth Bus

Fifth Bus

Sixth Bus

Command

Bus

Cycle

Cycle

Cycle

Cycle

Cycle

Cycle

Cycle

Addr

Data

Addr

Data Addr

Data Addr

Data

Addr

Data Addr Data

Read(Note 5)

1

RA

RD

Reset(Note 6)

1

XXX

F0

Autoselect(Note 7)

Manufacturer ID

4

555

AA

2AA

55

555

90

X00

C2

Device ID

4

555

AA

2AA

55

555

90

X01

22FC

Secured Sector

4

555

AA

2AA

55

555

90

x03

see

Factory Protect

Note9

Enter Secured Silicon

3

555

AA

2AA

55

555

88

Sector

Exit Secured Silicon

4

555

AA

2AA

55

555

90

xxx

00

Sector

Porgram

4

555

AA

2AA

55

555

A0

PA

PD

Chip Erase

6

555

AA

2AA

55

555

80

555

AA

2AA

55

555

10

TABLE4. MX26L6420 COMMAND DEFINITIONS

Notes:

1.See Table 1 for descriptions of bus operations.

2.All values are in hexadecimal.

3.Except when reading array or autoselect data, all bus cycles are write operation.

4.Address bits are don't care for unlock and command cycles, except when PA is required.

5.No unlock or command cycles required when device is in read mode.

6.The Reset command is required to return to the read mode when the device is in the autoselect mode or if Q5 goes

high.

7.The fourth cycle of the autoselect command sequence is a read cycle.

8.In the third and fourth cycles of the command sequence, set A21=0.

8.Command is valid when device is ready to read array data or when device is in autoselect mode.

9.The data is 88h for factory locked and 08h for non-factory locked.