A29040A Series
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.
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
Table 3. A29040A Autoselect Codes (High Voltage Method)
Identifier Code on
I/O7 - I/O0
Description
A18 - A16 A15 - A10 A9
A8 - A7 A6 A5 - A2 A1
AO
Manufacturer ID: AMIC
Device ID: A29040A
X
X
X
X
VID
VID
X
X
VIL
VIL
X
X
VIL
VIL
VIL
VIH
37h
86h
0lh (protected)
00h (unprotected)
Sector Protection
Verification
Sector
Address
X
VID
VID
X
X
VIL
VIL
X
X
VIH
VIH
VIL
VIH
Continuation ID
X
X
7Fh
Sector Protection/Unprotection
Write Pulse "Glitch" Protection
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.
Noise pulses of less than 5ns (typical) on
do not initiate a write cycle.
,
or
OE CE
WE
Logical Inhibit
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.
Write cycles are inhibited by holding any one of
=VIL,
OE
CE
= VIH or
= VIH. To initiate a write cycle,
and
CE
WE
must be a logical zero while
is a logical one.
OE
WE
Power-Up Write Inhibit
If
Hardware Data Protection
=
= VIL and
= VIH during power up, the
OE
WE
device does not accept commands on the rising edge of
. The internal state machine is automatically reset to
CE
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.
WE
reading array data on the initial power-up.
PRELIMINARY
(August, 2001, Version 0.1)
6
AMIC Technology, Inc.
AMICC [ AMIC TECHNOLOGY ]
