AT49BV512

3

DATA POLLING: The AT49BV512 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 AT49BV512

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 AT49BV512 in

the following ways: (a) V

(typical), 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 pro-

gram cycle.

INPUT LEVELS: While operating with a 2.7V to 3.6V

power supply, the address inputs and control inputs

(OE,

CE and WE) may be driven from 0 to 5.5V without

adversely affecting the operation of the device. The I/O

lines can only be driven from 0 to V

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