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A29L040A-70

512K X 8 Bit CMOS 3.0 Volt-only, Uniform Sector Flash Memory

AMIC Technology 

A29L040A Series

Autoselect Mode

The autoselect mode provides manufacturer and device

identification, and sector protection verification, through

identifier codes output on I/O7 - I/O0. 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 VID (11.5V to 12.5 V) on address pinA9. Address

pins A6, A1, and AO must be as shown in 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 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 I/O7 - I/O0.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 VID. See "Command Definitions" for details on using

the autoselect mode.

Table 3. A29L040A Autoselect Codes (High Voltage Method)

Description

Manufacturer ID: AMIC

Device ID: A29L040A

Sector Protection

Verification

A18 - A16 A15 - A10 A9 A8 - A7 A6 A5 - A2 A1 AO

X

X

Sector

Address

X

VID

X

VIL

X

VIL VIL

X

VID

X

VIL

X

VIL VIH

X

VID

X

VIL

X

VIH VIL

Continuation ID

X

X

VID

X

VIL

X

VIH

VIH

Identifier Code on

I/O7 - I/O0

37h

92h

01h (protected)

00h (unprotected)

7Fh

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 using

programming equipment. The procedure requires a high

voltage (VID) on address pin A9 and the control pins.

The 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 requirement of command unlocking sequence 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

VCC power-up transitions, or from system noise. The device

is powered up to read array data to avoid accidentally writing

data to the array.

Write Pulse "Glitch" Protection

Noise pulses of less than 5ns (typical) on OE , CE or WE

do not initiate a write cycle.

Logical Inhibit

Write cycles are inhibited by holding any one of OE =VIL,

CE = VIH or WE = VIH. To initiate a write cycle, CE and

WE must be a logical zero while OE is a logical one.

Power-Up Write Inhibit

If WE = CE = VIL and OE = VIH during power up, the

device does not accept commands on the rising edge of

WE . The internal state machine is automatically reset to

reading array data on the initial power-up.

PRELIMINARY (March, 2005, Version 0.0)

6

AMIC Technology, Corp.

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