AM29F100 AMD [Advanced Micro Devices], AM29F100 Datasheet - Page 10

• Manufacturer Part Number: AM29F100
• Description: 1 Megabit (128 K x 8-bit/64 K x 16-bit) CMOS 5.0 Volt-only, Boot Sector Flash Memory
• Manufacturer: AMD [Advanced Micro Devices]

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 pro-
tected sectors.
Sector protection/unprotection must be implemented
using programming equipment. The procedure re-
quires a high voltage (V
control pins. Details on this method are provided in a
supplement, publication number 20373. Contact an
AMD representative to obtain a copy of the appropriate
document.
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 ExpressFlash™ Service. Contact an
AMD representative for details.
It is possible to determine whether a sector is protected
or unprotected. See “Autoselect Mode” for details.
Temporary Sector Unprotect
This feature allows temporary unprotection of previ-
ously protected sectors to change data in-system.
The Sector Unprotect mode is activated by setting the
RESET# pin to V
tected sectors can be programmed or erased by se-
lecting the sector addresses. Once V
from the RESET# pin, all the previously protected
sectors are protected again. Figure 1 shows the algo-
rithm, and the Temporary Sector Unprotect (Figure
17) diagram shows the timing waveforms, for this fea-
ture.
10
ID
. During this mode, formerly pro-
ID
) on address pin A9 and the
ID
is removed
Am29F100
Notes:
1. All protected sectors unprotected.
2. All previously protected sectors are protected once
Figure 1. Temporary Sector Unprotect Operation
again.
Program Operations
Completed (Note 2)
Temporary Sector
Perform Erase or
RESET# = V
RESET# = V
Unprotect
(Note 1)
START
ID
IH
18926C-6