Table 3. Am29F080B Autoselect Codes (High Voltage Method)
to to to to
CE# OE# WE# A12 A10 A9 A7 A6 A2 A1 A0
Manufacturer ID: AMD L L H X X VID X L X L L
Device ID: Am29F080B L L H X X VID X L X L H
H SGA X VID X L X H L
Legend: L = Logic Low = VIL, H = Logic High = VIH, SGA = Sector Group Address, X = Don’t care.
Note: The system may also autoselect information in-system via the command register. See Table 5.
Sector Group Protection/Unprotection
The hardware group sector protection feature dis-
ables both program and erase operations in any sec-
tor group. Each sector group consists of two adjacent
sectors. Table 4 shows how the sectors are grouped,
and the address range that each sector group con-
tains. The hardware sector group unprotection fea-
ture re-enables both program and erase operations in
previously protected sector groups.
Sector group protection/unprotection must be imple-
mented using programming equipment. The procedure
requires a high voltage (VID) on address pin A9 and the
control pins. Details on this method are provided in a
supplement, listed in publication number 19945. Con-
tact an AMD representative to obtain a copy of the ap-
The device is shipped with all sectors unprotected.
AMD offers the option of programming and protecting
sector groups 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 group is
protected or unprotected. See “Autoselect Mode” for
Table 4. Sector Group Addresses
Group A19 A18 A17
Temporary Sector Group Unprotect
This feature allows temporary unprotection of previ-
ously protected sector groups to change data in-sys-
tem. The Sector Group Unprotect mode is activated
by setting the RESET# pin to VID. During this mode,
formerly protected sector groups can be programmed
or erased by selecting the sector group addresses.
Once VID is removed from the RESET# pin, all the
previously protected sector groups are
protected again. Figure 1 shows the algorithm, and
the Temporary Sector Group Unprotect diagram
shows the timing waveforms, for this feature.
RESET# = VID
Perform Erase or
RESET# = VIH
Temporary Sector Group
Completed (Note 2)
1. All protected sector groups unprotected.
2. All previously protected sector groups are protected
Figure 1. Temporary Sector Group Unprotect