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A29L004 View Datasheet(PDF) - AMIC Technology

Part NameDescriptionManufacturer
A29L004 512K X 8 Bit CMOS 3.0 Volt-only, Boot Sector Flash Memory AMICC
AMIC Technology AMICC
A29L004 Datasheet PDF : 39 Pages
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A29L004 Series
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.
It is possible to determine whether a sector is protected or
unprotected. See “Autoselect Mode” for details.
Sector protection / unprotection can be implemented via two
methods. The primary method requires VID on the
RESETpin only (N/A on 32-pin PLCC & (s)TSOP packages),
and can be implemented either in-system or via programming
equipment. Figure 2 shows the algorithm and the Sector
Protect / Unprotect Timing Diagram illustrates the timing
waveforms for this feature. This method uses standard
microprocessor bus cycle timing. For sector unprotect, all
unprotected sectors must first be protected prior to the first
sector unprotect write cycle. The alternate method 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.
Temporary Sector Unprotect (N/A on 32-pin PLCC &
(s)TSOP packages)
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 VID.
During this mode, formerly protected sectors can be
programmed or erased by selecting the sector addresses.
Once VID is removed from the RESET pin, all the previously
protected sectors are protected again. Figure 1 shows the
algorithm, and the Temporary Sector Unprotect diagram
shows the timing waveforms, for this feature.
START
RESET = VID
(Note 1)
Perform Erase or
Program Operations
RESET = VIH
Temporary Sector
Unprotect
Completed (Note 2)
Notes:
1. All protected sectors unprotected.
2. All previously protected sectors are protected once again.
Figure 1. Temporary Sector Unprotect Operation
PRELIMINARY (October, 2002, Version 0.0)
10
AMIC Technology, Corp.
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