Datasheet

 2015 Microchip Technology Inc. DS20005119G-page 81
SST26VF064B / SST26VF064BA
11.1 Mapping Guidance Details
The SFDP Memory Organization/Block Protection Bit
Mapping defines the memory organization including
uniform sector/block sizes and different contiguous
sectors/blocks sizes. In addition, this bit defines the
number of these uniform and different sectors/blocks
from address 000000H to the full range of Memory and
the associated Block Locking Register bits of each sec-
tor/block.
Each major Section is defined as follows:
A Major Section consists of Sector Type Number, Num-
ber of Sector of this type, and the Block-Protection Bit
Start/End locations. This is tied directly to JEDEC Flash
Parameter Table Sector Size Type (in 7th DWORD and
8th DWORD section). Note that the contiguous 4KByte
Sectors across the full memory range are not included
on this section because they are not defined in the
JEDEC Flash Parameter Table Sector Size Type sec-
tion. Only the sectors/blocks that are dependently tied
with the Block-Protection Register bits are defined. A
major section is a partition of contiguous same-size
sectors/blocks. There will be several Major Sections as
you dissect across memory from 000000h to the full
range. Similar sector/block size that re-appear may be
defined as a different Major Section.
11.1.1 SECTOR TYPE NUMBER
Sector Type Number is the sector/block size typed
defined in JEDEC Flash Parameter Table: SFDP
address locations 4CH, 4EH, 50H, and 52H. For SFDP
address location 4CH, which is Sector Type 1, the size
is represented by 01H; SFDP address location 4EH,
Sector Type 2, size is represented by 02H; SFDP
address location 50H, Sector Type 3, size is repre-
sented by 03H; and SFDP address location 52H, Sec-
tor Type 4, size is represented by 04H. Contiguous
Same Sector Type # Size can re-emerge across the
memory range and this Sector Type # will indicate that
it is a separate/independent Major Section from the
previous contiguous sectors/blocks.
11.1.2 NUMBER OF SECTORS
Number of Sectors represents the number of contigu-
ous sectors/blocks with similar size. A formula calcu-
lates the contiguous sectors/blocks with similar size.
Given the sector/block size, type, and the number of
sectors, the address range of these sectors/blocks can
be determined along with specific Block Locking Reg-
ister bits that control the read/write protection of each
sectors/blocks.
25EH A23:A16 07H
Section 5 Block Protection Bit Start
((2
m
) +1)+ c, c=07H or 7, m= 7 for 64 Mb
Address bits are Read Lock bit locations and Even Address bits are Write
Lock bit locations. The most significant (left-most) bit indicates the sign of
the integer; it is sometimes called the sign bit. If the sign bit is zero, then
the number is greater than or equal to zero, or positive. If the sign bit is
one then the number is less than zero or negative.
25FH A31:A24 0EH
Section 5 (Top) Block Protection Bit End
(((2
m
) +1)+ c, c=0EH or 14, m= 7 for 64 Mb,
Address bits are Read Lock bit locations and Even Address bits are Write
Lock bit locations. The most significant (left-most) bit indicates the sign of
the integer; it is sometimes called the sign bit. If the sign bit is zero, then
the number is greater than or equal to zero, or positive. If the sign bit is
one then the number is less than zero or negative.
1. See “Mapping Guidance Details” for more detailed mapping information
TABLE 11-1: SERIAL FLASH DISCOVERABLE PARAMETER (SFDP) (CONTINUED) (16 OF 16)
Address Bit Address Data Comments
TABLE 11-2: SECTION DEFINITION
Major Section X Section X: Sector Type Number
Section X: Number of Sectors
Section X: Block-Protection Register Bit Start Location
Section X: Block-Protection Register Bit End Location