P R E L I M I N A R Y
Table 9. Bottom Boot Sector/Sector Block
Addresses for Protection/Unprotection
diagram. This method uses standard microprocessor
bus cycle timing. For sector unprotect, all unprotected
sectors must first be protected prior to the first sector
unprotect write cycle.
Sector/Sector Block
Size
Sector
A20–A12
SA70
111111XXX
64 Kbytes
The device is shipped with all sectors unprotected.
111110XXX,
111101XXX,
111100XXX
It is possible to determine whether a sector is pro-
tected or unprotected. See the Autoselect Mode
section for details.
SA69-SA67
192 (3x64) Kbytes
SA66-SA63
SA62-SA59
SA58-SA55
SA54-SA51
SA50-SA47
SA46-SA43
SA42-SA39
SA38-SA35
SA34-SA31
SA30-SA27
SA26-SA23
SA22–SA19
SA18-SA15
SA14-SA11
1110XXXXX
1101XXXXX
1100XXXXX
1011XXXXX
1010XXXXX
1001XXXXX
1000XXXXX
0111XXXXX
0110XXXXX
0101XXXXX
0100XXXXX
0011XXXXX
0010XXXXX
0001XXXXX
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
256 (4x64) Kbytes
Write Protect (WP#)
The Write Protect function provides a hardware
method of protecting certain boot sectors without
using VID. This function is one of two provided by the
WP#/ACC pin.
If the system asserts VIL on the WP#/ACC pin, the de-
vice disables program and erase functions in the two
“outermost” 8 Kbyte boot sectors independently of
whether those sectors were protected or unprotected
using the method described in “Autoselect Mode”. The
two outermost 8 Kbyte boot sectors are the two sec-
tors containing the lowest addresses in a
top-boot-configured device, or the two sectors contain-
ing the highest addresses in a top-boot-configured
device.
000011XXX,
000010XXX,
000001XXX
SA10-SA8
192 (3x64) Kbytes
If the system asserts VIH on the WP#/ACC pin, the de-
vice reverts to whether the two outermost 8 Kbyte boot
sectors were last set to be protected or unprotected.
That is, sector protection or unprotection for these two
sectors depends on whether they were last protected
or unprotected using the method described in “Autose-
lect Mode”.
SA7
SA6
SA5
SA4
SA3
SA2
SA1
SA0
000000111
000000110
000000101
000000100
000000011
000000010
000000001
000000000
8 Kbytes
8 Kbytes
8 Kbytes
8 Kbytes
8 Kbytes
8 Kbytes
8 Kbytes
8 Kbytes
Note that the WP#/ACC pin must not be left floating or
unconnected; inconsistent behavior of the device may
result.
Temporary Sector/Sector Block Unprotect
The hardware sector protection feature disables both
program and erase operations in any sector. The hard-
ware sector unprotection feature re-enables both
program and erase operations in previously protected
sectors. Note that the sector unprotect algorithm un-
protects all sectors in parallel. All previously protected
sectors must be individually re-protected. To change
data in protected sectors efficiently, the temporary
sector un protect function is available. See “Temporary
Sector/Sector Block Unprotect”.
(Note: For the following discussion, the term “sector”
applies to both sectors and sector blocks. A sector
block consists of two or more adjacent sectors that are
protected or unprotected at the same time (see Table
8).
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 (11.5 V – 12.5 V). During this mode,
formerly protected sectors can be programmed or
erased by selecting the sector addresses. Once VID is
removed from the RESET# pin, all the previously pro-
tected sectors are protected again. Figure 1 shows the
algorithm, and Figure 25 shows the timing diagrams,
for this feature.
Sector protection and unprotection can be imple-
mented as follows.
Sector protection and unprotection requires VID on the
RESET# pin only, and can be implemented either
in-system or via programming equipment. Figure 2
shows the algorithms and Figure 26 shows the timing
July 19, 2002
Am49DL32xBG
19
CYPRESS [ CYPRESS ]
