AM29F004B AMD [Advanced Micro Devices], AM29F004B Datasheet - Page 12

• Manufacturer Part Number: AM29F004B
• Description: 4 Megabit (512 K x 8-Bit) CMOS 5.0 Volt-only Boot Sector Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

Autoselect Mode
The autoselect mode provides manufacturer and device iden-
tification, and sector protection verification, through identifier
codes output on DQ7–DQ0. This mode is primarily intended
for programming equipment to automatically match a device
to be programmed with its corresponding programming algo-
rithm. However, the autoselect codes can also be accessed
in-system through the command register.
When using programming equipment, the autoselect mode
requires V
must be as shown in Autoselect Codes (High Voltage
Method) table. In addition, when verifying sector protection,
L = Logic Low = V
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.
The primary method requires V
can be implemented either in-system or via programming
equipment.
and
18, on page 29
standard microprocessor bus cycle timing in addition to the
sector unlock and sector relock sequences. For sector unpro-
tect, all unprotected sectors must first be protected prior to
the first sector unprotect write cycle.
10
Manufacturer ID: AMD
Device ID:
Am29F004B (Top Boot Block)
Device ID:
Am29F004B (Bottom Boot Block)
Sector Protection Verification
Figure 16, on page
ID
Figure 1, on page 11
Description
on address pin A9. Address pins A6, A1, and A0
show the timing diagrams. This method uses
IL
, H = Logic High = V
28,
Figure 17, on page
Table 4. Am29F004B Autoselect Codes (High Voltage Method)
ID
and 2 show the algorithms
on the OE# pin only, and
IH
A D V A N C E
CE#
, SA = Sector Address, X = Don’t care.
L
L
L
L
L
L
OE#
L
L
L
L
L
L
28, and
WE#
H
H
H
H
H
H
Figure
Am29F004B
A18
A13
SA
I N F O R M A T I O N
to
X
X
X
A12
A10
to
X
X
X
X
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 neces-
sary bits are set as required, the programming equipment
may then read the corresponding identifier code on DQ7–
DQ0.
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 V
for details on using the autoselect mode.
The alternate method intended only for programming equip-
ment required V
is compatible with programmer routines written for earlier 5.0
volt-only AMD Flash devices. Publication number 22289 con-
tains further details; contact an AMD representative to
request a copy.
The device is shipped with all sectors unprotected. AMD
offers the option of programming and protecting sectors at its
factory prior to shipping the device through AMD’s Express-
Flash™ Service. Contact an AMD representative for details.
It is possible to determine whether a sector is protected or
unprotected. See
V
V
V
V
A9
ID
ID
ID
ID
A8
A7
to
X
X
X
X
ID
ID
Autoselect Mode on page 10
on address pin A9 and OE#. This method
A6
. See
L
L
L
L
A5
A2
Command Definitions on page 13
to
X
X
X
X
A1
H
L
L
L
A0
H
H
L
L
01h (protected)
(unprotected)
for details.
DQ7
DQ0
7Bh
01h
77h
00h
to
8/5/05