FLASH
Austin Semiconductor, Inc.
DATA PROTECTION
Hardware-Sector Protection Feature
This feature disables both programming and erase opera-
tions on any combination of one to eight sectors. Commands
to program or erase a protected sector do not change the data
contained in the sector. The data-polling and toggle bits oper-
ate for 2ms to 100ms and then return to valid data. This feature
is enabled using high-voltage V
ID
(11.5V to 12V) on address
pin A9 and control pin OE\ and V
IL
on control pin CE\.
The device is delivered with all sector unprotected.
Sector-unprotected mode is available to unprotect protected
sectors.
Sector Protect Operation
The sector protect mode is activated when WE\=V
IH
,
CE\=V
IL
, and address pin A9 and control pin OE\ are forced to
V
ID
. The sector-select address pins A18, A17, and A16 are
used to select the sector to be protected. Address pins A0-A15
and I/O pins DQ0- DQ7 must be stable and can be V
IL
or V
IH
.
Once the addresses are stable, WE\ is pulsed low for 100 ms.
The operation begins on the falling edge of WE\ and terminates
on the raising edge of WE\.
Sector Protect Verify
Verification of sector protection is activated when
WE\=V
IH
, CE\=V
IL
, OE\=V
IL
, and address pin A9 is V
ID
.
Address pins A0 and A6 are set to V
IL
, and A1 is set to V
IH
.
The sector address pins A18, A17, and A16 select the sector to
be verified. The other addresses can be V
IH
or V
IL
. If the
sector selected if protected, the DQs output O1. If the sector
selected is unprotected the DQs output is 00.
Sector protection can also be verified using the algorithm-
selection command. After issuing the three bus-cycle command
sequence, the sector protection status can be read on DQ0. Set
address pins A0 = V
IL
, A1 = V
IH
, and A6 = V
IL
. Sector
address pins A18, A17, and A16 select the sector to be verified.
The remaining addresses are set to V
IL
. If the sector selected is
protected. DQ0 outputs a 1 state, and if the sector selected is
unprotected DQ0 outputs a 0 state. This mode remains in effect
until another valid sequence is written to the device.
Sector Unprotect
Prior to sector unprotected, all sectors should be protected
using the sector unprotect mode. The sector unprotect is acti-
vated when WE\=V
IH
, and control pin CE\, OE\, and address
pin A9 are forced to V
ID
. Address pins A6, A12, and A16 are
set to V
IH
. The sector select address pins A18, A17, and A16
can be V
IL
or V
IH
. All eight sectors are unprotected in parallel.
Once the inputs are stable, WE\ is pulsed low for 10ms. The
unprotect operation begins on the falling edge of WE\ and
terminates on the raising edge of WE\.
Sector Unprotect Verify
Verification of the sector unprotected is activated when
WE\ = V
IH
, OE\ = V
IL
, CE\ = V
IL
, and address pin A9 = V
ID
.
Select the sector to be verified. Address A1 and A6 are set to
V
IH
and A0 to V
IL
. The other addresses can be V
IL
or V
IH
. If
the sector selected is protected, the DQs output a 01, if sector
selected is unprotected the DQs output a 00. Sector unprotect
can also be read using the algorithm selection command.
Low VCC Write Lock Out
During power-up and power-down , are locked out for V
CC
less than VLKO If V
CC
<VLKO, the command inputs is dis-
abled and the device is reset to the read mode. On power-up, if
CE\=V
IL
, WE\= V
IL
, and OE\=V
IH
, the device does not accept
commands on the raising edge of WE. The device automati-
cally powers up in the read mode.
Glitiching
Pulses of less than 5ns (typical) on WE\, OE\, and CE\ will
not issue a write cycle.
Power Supply Consideration
Each device should have as a maximum of 0.1 mF ceramic
capacitor connected between Vcc and Vss to suppress circuit
noise. Printed circuit traces to Vcc should have be appropriate
to handle the current demand and minimize inductance.
AS8F512K32
AS8F512K32
Rev. 5.2 09/07
Austin Semiconductor, Inc. reserves the right to change products or specifications without notice.
5
AUSTIN [ AUSTIN SEMICONDUCTOR ]
