Table 4. Am29LV200 Autoselect Codes (High Voltage Method)
Mode CE# OE# WE# A12 A10 A9 A7 A6 A2 A1 A0 DQ15
Manufacturer ID: AMD
H X X VID X L X L L
X X VID X L X L H
(Top Boot Block)
X X VID X L X L H
Sector Protection Verification L
H SA X VID X L X H L
L = Logic Low = VIL, H = Logic High = VIH, SA = Sector Address, X = Don’t care.
The hardware sector protection feature disables both
program and erase operations in any sector. The hard-
ware sector unprotection feature re-enables both pro-
gram and erase operations in previously protected
Sector protection/unprotection must be implemented
using programming equipment.The procedure requires
a high voltage (VID) on address pin A9 and OE#. De-
tails on this method are provided in a supplement, pub-
lication number 21226. 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 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 RE-
SET# pin to VID. During this mode, formerly protected
sectors can be programmed or erased by selecting the
sector addresses. Once VID is removed from the RE-
SET# pin, all the previously protected sectors are
protected again. Figure 1 shows the algorithm, and
Figure 21 shows the timing diagrams, for this feature.
RESET# = VID
Perform Erase or
RESET# = VIH
1. All protected sectors unprotected.
2. All previously protected sectors are protected once
Figure 1. Temporary Sector Unprotect Operation