AUSTIN SEMICONDUCTOR, INC.
Austin Semiconductor, Inc.
Temporary Sector Unprotect
This feature allows temporary un-protection of previously
protected sectors to change data in-system. Setting the RESET\
pin to VID activates the sector Unprotect mode. 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. The diagram below depicts the algorithm
flow for this operation.
AS8FLC1M32
FLASH
Write Pulse “GLITCH” Protection
Noise pulses of less than 5ns (typical) on OE\, CSx\ or WEx\ do
not initiate a WRITE cycle.
Logical Inhibit
WRITE cycles are inhibited by holding any one of OE\=VIL,
CSx\=VIH or WEx\=VIH. To initiate a WRITE cycle, CSx\ and
WEx\ must be a logical zero while OE\ is a logical one.
Power-Up WRITE Inhibit
Temporary Sector Unprotect Diagram
Start
If WEx\=CSx\=VIL and OE\=VIH during power-up, the device
does not accept commands on the rising edge of WEx\. The
internal state machine is automatically reset to READING array
data on power-up.
RESET\ = VID
(Note 1)
Command Definitions
Writing specific address and data commands or sequences
into the command register initiates device operations. The
COMMAND REGISTER TABLE defines the valid register
command sequences for this device Module. WRITING
incorrect address and data values or WRITING them in the
improper sequence resets the device to READING array data.
All addresses are latched on the falling edge of WEx\ or CSx\,
whichever happens later. All data is latched on the rising edge
of WEx\ or CSx\, whichever happens first. Refer to the AC
timing references for correct timings of the appropriate signals.
Perform Erase or
Program
Operations
RESET\ = VIH
Temporary Sector
Unprotect
Completed
(Note 2)
Reading Array Data
NOTES:
1. All protected sectors unprotected
2. All previously protected sectors are
protected once again
The device is automatically set to READING Array data after
device power-up. No commands are required to retrieve data.
The device is also ready to READ data after completing an
Embedded Program or Embedded Erase operation.
After the device accepts an ERASE Suspend command, the
device enters the ERASE Suspend Mode. The system can
read array data using the standard READ timings, except that
if it READS at an address within Erase-Suspended sectors, the
device outputs status data. After completing a programming
operation in the Erase Suspend Mode, the system may once
again READ array data with the same exception.
The system must issue the reset command to re-enable the
device for reading array data if DQ5, DQ13, DQ21 and DQ29
goes high, or while in the autoselect mode.
Hardware Data Protection
The command sequence requirements of UNLOCK cycles for
PROGRAMMING or ERASING provides data protection
against inadvertent WRITES. 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 and power-down transitions, or from system noise.
Low VCC WRITE Inhibit
When VCC is less than VLKO, the device does not accept any
WRITE cycles. This protects data during VCC power-up and
power-down. The system must provide the proper signals to
the control pins to prevent unintentional WRITES when VCC
is greater than VLKO.
AS8FLC1M32B
Rev. 3.3 05/08
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
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