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M39432

Figure 14. Write Mode AC Waveforms (EE or EF controlled)

2. Addresses are latched on the falling edge of E, Data are latched on the rising edge of E.

E

(1)

AI01954

G

W

A0-A18

DQ0-DQ7

VALID

VALID

VCC

tVCHWL

tEHWH

tEHEL

tWLEL

tAVEL

tEHGL

tELAX

tEHDX

WRITE CYCLE

tDVEH

tELEH

tGHEL

DQ0-DQ7

RB

tWHRL

unprotected. Following the protection of a new

sector, the status is found on DQ0 as shown by the

sequence in Figure 8. Following the unprotection

of all sectors, the status is found on DQ0-DQ7 as

shown by the sequence in Figure 9.

These

two

Verify

Sector

Protection

Status

operations are implemented like Read operations,

but provide a more severe test of the correct

functioning of the device than does a Read Sector

Protection instruction (as shown in Table 4).

Reset Instruction

Reset is an instruction involving either one write

operation or three write operations (as shown in

Table 4).

The Reset instruction returns the memory to its

Read mode, and resets any errors in the Status

Register. If the Reset instruction is issued during a

Sector Erase cycle, or during a Programming

cycle, then the internal logic will take up to 10

µs to

abort. During the abort period, no valid data can be

read from the memory. Issuing a Reset command

during a sector Erase cycle will leave invalid data

in the memory.

GLOSSARY

Block: Flash memory block (4 Mbit) or EEPROM

block (256 Kbit)

Bulk: the whole Flash memory block (4 Mbit)

Sector: 64 KByte of Flash memory

Page: 64 Bytes of EEPROM

Program and Write: Programming (in the Flash

memory block) and Writing (to the EEPROM

block) and are not the same:

s

Flash memory bytes are programmed using the

Program instruction (as shown in Table 4). This

is used to change any bit values from ‘1’s to ‘0’s,

where appropriate. As it is impossible to

program bits from ‘0’s to ‘1’s, it is necessary to

run a Sector Erase instruction before any byte

overwriting can be performed.

s

EEPROM bytes are written using a simple

operation (Table 3).

SDP: Software Data Protection. This is used for

protecting the EEPROM block against inadvertent

Write

operations

(for

example,

in

noisy

environments).