a290011tx-90f AMIC Technology Corporation, a290011tx-90f Datasheet - Page 8

• Manufacturer Part Number: a290011tx-90f
• Description: 128k X 8 Bit Cmos 5.0 Volt-only, Boot Sector Flash Memory
• Manufacturer: AMIC Technology Corporation

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 (V
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 V
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
Logical Inhibit
Write cycles are inhibited by holding any one of
Power-Up Write Inhibit
If
device does not accept commands on the rising edge of
reading array data on the initial power-up.
Temporary Sector Unprotect (N/A A290011)
This feature allows temporary unprotection of previous
protected sectors to change data in-system. The Sector
Unprotect mode is activated by setting the RESET pin to
V
programmed or erased by selecting the sector addresses.
Once V
previously protected sectors are protected again. Figure 1
shows the algorithm, and the Temporary Sector Unprotect
diagram shows the timing waveforms, for this feature.
(December, 2004, Version 1.3)
CE
WE
WE
WE
ID
WE
. During this mode, formerly protected sectors can be
= V
. The internal state machine is automatically reset to
do not initiate a write cycle.
must be a logical zero while
=
IH
ID
CE
ID
or
) on address pin A9 and the control pins.
is removed from the RESET pin, all the
WE
= V
CC
IL
= V
power-up transitions, or from system
and
IH
. To initiate a write cycle,
OE
= V
OE
IH
during power up, the
is a logical one.
OE
OE
,
CE
CE
=V
and
or
IL
,
7
Notes:
1. All protected sectors unprotected.
2. All previously protected sectors are protected once again.
Figure 1. Temporary Sector Unprotect Operation
Program Operations
Completed (Note 2)
Temporary Sector
Perform Erase or
RESET = V
RESET = V
Unprotect
A29001/A290011 Series
(Note 1)
START
AMIC Technology, Corp.
ID
IH