FLASH

AS29F040

Micross Components reserves the right to change products or specifications without notice.

5

AS29F040

Rev. 2.3 01/10

When the system is not reading or writing to the device, it

can place the device in the standby mode. In this mode, current

consumption is greatly reduced, and the outputs are placed in

the high impedance state, independent of the OE\ input.

The device enters the CMOS standby mode when the CE\

pin is held at V

voltage range than V

mode when CE\ is held at V

access time (t

If the device is deselected during erasure or program-

ming, the device draws active current until the operation is

completed.

I

current specification.

Output Disable Mode

When the OE\ input is at V

disabled. The output pins are placed in the high impedance

state.

Autoselect Mode

The autoselect mode provides manufacturer and device

identification, and sector protection verification, through

identifier codes output on DQ7 - DQ0. This mode is primarily

intended for programming equipment to automatically match a

device to be programmed with its corresponding programming

algorithm. However, the autoselect codes can also be accessed

in-system through the command register.

When using programming equipment, the autoselect mode

requires V

A6, A1, and A0 must be as shown in the Autoselect Codes (High

Voltage Method) table. In addition, when verifying

sector

protection, the sector address must appear on the

appropriate

highest order address bits. Refer to the

corresponding

Sector Address Tables. The Command

Definitions table

TABLE 2: SECTOR ADDRESSES TABLE

shows the remaining address bits that are don’t care. When

all necessary bits have been set as required, the programming

equipment may then read the corresponding identifier code on

DQ7 - DQ0

To access the autoselect codes in-system, the host system

can issue the autoselect command via the command register, as

shown in the Command Definitions table. This method does

not require V

using the autoselect mode.

Sector Protection/Unprotection

The hardware sector protection feature disables both

program and erase operations in any sector. The hardware

sector unprotection feature re-enables both program and erase

operations in previously protected sectors.

Sector protection/unprotection must be implemented us-

ing programming equipment. The procedure requires a high

voltage (V

device is shipped with all sectors unprotected. It is possible

to determine whether a sector is protected or unprotected. See

“Autoselect Mode” for details.

Hardware Data Protection

The command sequence requirement of unlock cycles

for programming or erasing provides data protection against

inadvertent writes (refer to the Command Definitions table).

In addition, the following hardware data protection measures

prevent accidental erasure or programming, which might

otherwise be caused by spurious system level signals during

V

noise.

Low V

CC

Write Inhibit

When V

any write cycles. This protects data during V

SECTOR

A18

A17

A16

ADDRESS RANGE

SA0

0

0

0

00000h - 0FFFFh

SA1

0

0

1

10000h - 1FFFFh

SA2

0

1

0

20000h - 2FFFFh

SA3

0

1

1

30000h - 3FFFFh

SA4

1

0

0

40000h - 4FFFFh

SA5

1

0

1

50000h - 5FFFFh

SA6

1

1

0

60000h - 6FFFFh

SA7

1

1

1

70000h - 7FFFFh