Temperature Under Bias................. -55

°C to +125°C

Storage Temperature...................... -65

°C to +150°C

All Input Voltages

(including NC Pins)

with Respect to Ground ................... -0.6V to +6.25V

All Output Voltages

Voltage on OE

with Respect to Ground .................. -0.6V to + 13.5V

*NOTICE: Stresses beyond those listed under “Absolute Maxi-

mum Ratings” may cause permanent damage to the device.

This is a stress rating only and functional operation of the

device at these or any other conditions beyond those indi-

cated in the operational sections of this specification is not

implied. Exposure to absolute maximum rating conditions

for extended periods may affect device reliability.

Absolute Maximum Ratings*

PRODUCT IDENTIFICATION: The product identification

mode identifies the device and manufacturer as Atmel. It

may be accessed by hardware or software operation. The

hardware operation mode can be used by an external pro-

grammer to identify the correct programming algorithm for

the Atmel product.

For details, see Operating Modes (for hardware operation)

or Software Product Identification. The manufacturer and

device code is the same for both modes.

DATA POLLING: The AT49F040 features DATA polling

to indicate the end of a program cycle. During a program

cycle an attempted read of the last byte loaded will result

in the complement of the loaded data on I/O7. Once the

program cycle has been completed, true data is valid on

all outputs and the next cycle may begin. DATA polling

may begin at any time during the program cycle.

TOGGLE BIT: In addition to DATA polling the AT49F040

provides another method for determining the end of a pro-

gram or erase cycle. During a program or erase operation,

successive attempts to read data from the device will re-

sult in I/O6 toggling between one and zero. Once the pro-

gram cycle has completed, I/O6 will stop toggling and valid

data will be read. Examining the toggle bit may begin at

any time during a program cycle.

HARDWARE DATA PROTECTION: Hardware features

protect against inadvertent programs to the AT49F040 in

(typical), the program function is inhibited. (b) Program in-

hibit: holding any one of OE low, CE high or WE high in-

hibits program cycles. (c) Noise filter: pulses of less than

15 ns (typical) on the WE or CE inputs will not initiate a

program cycle.

Device Operation (Continued)

Command Definition (in Hex)

Command

Sequence

Bus

Cycles

1st Bus

Cycle

2nd Bus

Cycle

3rd Bus

Cycle

4th Bus

Cycle

5th Bus

Cycle

6th Bus

Cycle

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Addr

Data

Read

1Addr

Chip Erase

6

5555

AA

2AAA

55

5555

80

5555

AA

2AAA

55

5555

10

Byte

Program

4

5555

AA

2AAA

55

5555

A0

Addr

Boot Block

Lockout

(1)

6

5555

AA

2AAA

55

5555

80

5555

AA

2AAA

55

5555

40

Product ID

Entry

3

5555

AA

2AAA

55

5555

90

Product ID

Exit

(2)

3

5555

AA

2AAA

55

5555

F0

Product ID

Exit

(2)

1

XXXX

F0

Note:

1. The 16K byte boot sector has the address range 00000H to 03FFFH.

2. Either one of the Product ID exit commands can be used.

AT49F040

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