18 Am49DL640BG March 8, 2002
PRELIMINARY
Sector/Sector Block Protection and
Unprotection
(Not e: F or t he fol lowin g discu ssi on, the ter m “sector”
applies to both sectors and sector blocks. A sector
block consis ts of t wo or m or e adjacent sec tors that are
protected o r unpro tected at the same time (see Table
6).
The hardw are sec tor pr otec tion f eature disab les bo th
program and erase operati ons in any sector . The hard-
ware sector unpro tection feature re- enables both pro -
gram and erase operations in previously protected
secto rs. S ector prote ction/ unpr otectio n can be imple -
mented via two methods.
Table 6. Am29DL640G Boot Sector/Secto r Blo ck
Addresses for Protection/Unpro t ection
Th e pri mary m ethod requ ir es V
ID
on the RESET# pin
only, and can be implemented either in-system or via
pro grammi ng eq uipme nt. Figu re 2 s hows th e al go-
rith ms and F igu re 26 sho ws t he timing d iagra m. Th is
meth od uses s tand ard mi cropr oces sor bu s cy cle tim-
ing. For sector unprotect, all unprotected sectors must
first be protected prior to the first sector unprotect writ e
cycle. N ote that the sec tor unprotect algor ithm unpro-
tects all sectors in parallel. All p reviously pro tected
sectors must be in dividually re-protected. To change
data in protected sectors efficiently, the temporary
sector unprotect function is available. See “Temporary
Sector Unprotect”.
Sector A2 1–A12
Sector/
Sect or Block Si ze
SA0 00000 00000 8 Kbytes
SA1 00000 00001 8 Kbytes
SA2 00000 00010 8 Kbytes
SA3 00000000 11 8 Kbytes
SA4 00000 00100 8 Kbytes
SA5 00000 00101 8 Kbytes
SA6 0000000110 8 Kbytes
SA7 0000 000 111 8 Kby t es
SA8–SA10
0000001XXX,
0000010XXX,
0000011XXX,
192 (3x64) Kbytes
SA11–SA14 00001XXXXX 256 (4x64) Kbytes
SA15–SA18 00 010XXXXX 256 (4x64) Kbytes
SA19–SA22 00011XXXXX 256 (4x64) Kbytes
SA23–SA26 00100XXXXX 256 (4x64) Kbytes
SA27-SA30 00101XXXXX 256 (4x64) Kbytes
SA31-SA34 0 0110XXXXX 256 (4x64) Kbytes
SA35-SA38 00111XXXXX 256 (4x64) Kbytes
SA39-SA42 01000XXXXX 256 (4x64) Kbytes
SA43-SA46 01001XXXXX 256 (4x64) Kbytes
SA47-SA50 01010XXXXX 256 (4x64) Kbytes
SA51-SA54 0 1011XXXXX 256 (4x64) Kbytes
SA55–SA58 01100XXXXX 256 (4x64) Kbytes
SA59–SA62 01101XXXXX 256 (4x64) Kbytes
SA63–SA6 6 01110XXXXX 256 (4x64) Kbyte s
SA67–SA7 0 01111XXXXX 256 (4x 64 ) Kbyte s
SA71–SA7 4 10000XXXXX 2 56 (4x 64 ) Kbytes
SA75–SA7 8 10001XXXXX 2 56 (4x 64 ) Kbytes
SA79–SA8 2 10010XXXXX 2 56 (4x 64 ) Kbytes
SA83–SA8 6 10011X XXXX 256 (4x64 ) Kbytes
SA87–SA9 0 10100XXXXX 2 56 (4x 64 ) Kbytes
SA91–SA9 4 10101XXXXX 2 56 (4x 64 ) Kbytes
SA95–SA9 8 10110X XXXX 256 (4x64 ) Kbytes
SA99–SA10 2 10111XXXXX 2 56 (4x 64 ) Kbyte s
SA103–SA106 110 00X XXXX 256 (4x64 ) Kbyte s
SA107–SA110 110 01X XXXX 256 (4x64 ) Kbyte s
SA111–SA114 110 10X XXXX 256 (4x64 ) Kbytes
SA115–SA118 11011XXXXX 2 56 (4x64 ) Kbytes
SA119–SA122 11100XXXXX 2 56 (4x64 ) Kbytes
SA123–SA126 11101XXXXX 256 (4x 64 ) Kbyte s
SA127–SA130 111 10XX XXX 256 (4x 64 ) Kbyte s
SA131–SA133
1111100XXX,
1111101XXX,
1111 110XXX
192 (3x64) Kbytes
SA134 1111111000 8 Kbytes
SA135 1111111001 8 Kbytes
SA136 1111111010 8 Kbytes
SA137 1111111011 8 Kbytes
SA138 1111111100 8 Kbytes
SA139 1111111101 8 Kbytes
SA140 1111111101 8 Kbytes
SA141 1111111111 8 Kbytes
Sector A21–A12
Sector/
Sector Block Size