M29F002T, M29F002NT, M29F002B
Write. Write operations are used to give Instruction
Commands to the memory or to latch input data to
be programmed.A write operation is initiated when
Chip Enable E is Low and Write Enable W is Low
with Output Enable G High. Addresses are latched
on the falling edge of W or E whichever occurs last.
Commands and InputData are latched on the rising
edge of W or E whichever occurs first.
protected in order to change stored data. The tem-
porary unprotection mode is activated by bringing
RPNC to VID. During the temporary unprotection
mode the previously protected blocks are unpro-
tected. A block can be selected and data can be
modified by executing the Erase or Program in-
struction with the RPNC signal held at VID. When
RPNC is returned to VIH, all the previously pro-
tected blocks are again protected.
Block Unprotection. All protected blocks can be
unprotected on programming equipment to allow
updating of bit contents. All blocks must first be
protected before the unprotection operation. Block
unprotection is activated when A9, G and E are at
VID and A12, A15 at VIH. The Block Unprotection
algorithm is shown in Figure 15. Unprotection is
initiated by the edge of W falling to VIL.After a delay
of 10ms, the unprotection operation is ended by
rising W to VIH. Unprotection verify is achieved by
bringing G and E to VIL while A0 is at VIL, A6 and
A1 are at VIH and A9 remains at VID. In these
conditions, reading the output data will yield 00h if
the block defined by the inputs A13-A17 has been
succesfully unprotected. Each block must be sepa-
rately verified by giving its address in order to
ensure that it has been unprotected.
Output Disable. The data outputs are high imped-
ance when the Output Enable G is High with Write
Enable W High.
Standby. The memory is in standby when Chip
Enable E is High and the P/E.C. is idle. The power
consumption is reduced to the standby level and
the outputsare high impedance, independentofthe
Output Enable G or Write Enable W inputs.
Automatic Standby. After 150ns of bus inactivity
and when CMOS levels are driving the addresses,
the chip automatically enters a pseudo-standby
mode where consumption is reduced to the CMOS
standby value, while outputs still drive the bus.
Electronic Signature. Two codes identifying the
manufacturer and the device can be read from the
memory. These codes allow programming equip-
ment or applications to automatically match their
interface to the characteristics of the M29F002.The
Electronic Signature is output by a Read operation
when the voltage applied toA9is atVID and address
input A1 is Low. The manufacturer code is output
when the Address input A0 is Low and the device
code when this input is High. Other Address inputs
are ignored.
INSTRUCTIONS AND COMMANDS
The Command Interface latchescommands written
to the memory. Instructions are made up from one
or more commands to perform Read MemoryArray,
Read Electronic Signature, Read Block Protection,
Program, Block Erase, Chip Erase, Erase Suspend
and Erase Resume. Commands are made of ad-
dress and data sequences.
The Electronic Signature can also be read, without
raising A9 to VID, by giving the memory the Instruc-
tion AS.
Block Protection. Each block can be separately
protected against Program or Erase on program-
ming equipment. Block protection provides addi-
tional data security, as it disables all program or
erase operations.This mode is activated when both
A9 and G are raised to VID and an address in the
block is applied on A13-A17. The Block Protection
algorithm is shown in Figure 14. Block protection is
initiated on the edge of W falling to VIL. Then after
a delay of 100µs, the edge of W rising to VIH ends
the protection operations. Block protection verify is
achieved by bringing G, E, A0 and A6 to VIL and A1
to VIH, while W is at VIH and A9 at VID. Under these
conditions, reading the data output will yield 01h if
the block defined by the inputs on A13-A17 is
protected. Any attempt to program or erase a pro-
tected block will be ignored by the device.
Table 7. Commands
Hex Code
00h
Command
Invalid/Reserved
10h
Chip Erase Confirm
Reserved
20h
30h
Block Erase Resume/Confirm
Set-up Erase
80h
Read Electronic Signature/
Block Protection Status
90h
A0h
B0h
F0h
Program
Erase Suspend
Read Array/Reset
Block Temporary Unprotection. This feature is
available on M29F002T and M29F002B only. Any
previously protected block can be temporarily un-
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