AT49F512

3

out feature has been activated and the block cannot be

programmed. The software product identification code

should be used to return to standard operation.

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 AT49F512 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 pro-

gram 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 AT49F512

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 result

in I/O6 toggling between one and zero. Once the program

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 AT49F512 in

the following ways: (a) V

ical), the program function is inhibited. (b) Program inhibit:

holding any one of OE low, CE high or WE high inhibits

program cycles. (c) Noise filter: Pulses of less than 15 ns

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

cycle.

Notes:

1. The 8K byte boot sector has the address range 0000H to 1FFFH.

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

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

1

Addr

D

OUT

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

D

IN

Boot Block

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

3

5555

AA

2AAA

55

5555

F0

Product ID

1

XXXX

F0

Absolute Maximum Ratings*

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

°C to +125°C

*NOTICE:

Stresses beyond those listed under “Absolute

Maximum Ratings” may cause permanent dam-

age to the device. This is a stress rating only and

functional operation of the device at these or any

other conditions beyond those indicated in the

operational sections of this specification is not

implied. Exposure to absolute maximum rating

conditions for extended periods may affect device

reliability.

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

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

Voltage on OE

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