25LC320 Datasheet, PDF (6/12 Pages) Microchip Technology – 32K 2.5V SPI Bus Serial EEPROM

25LC320
FIGURE 2-1: WRITE TO STATUS REGISTER AND/OR ARRAY FLOWCHART
CS Returns High
Write
No
to Status
Reg?
Yes
No
WEL = 1?
Yes
No
WP is low?
Yes
No
WPEN = 1?
Yes
Write to
Status Register
Do not write to
Status Register
Continue
Write
No
to array?
Yes
No
WEL = 1?
Yes
Write to the
Unprotected Block
To other
Commands
Do not write to
Array
From other
Commands
2.3 Write Status Register (WRSR)
The WRSR instruction allows the user to select one of
four protection options for the array by writing to the
appropriate bits in the status register. The array is
divided up into four segments. The user has the ability
to write protect none, one, two, or all four of the seg-
ments of the array. The partitioning is controlled as illus-
trated in Table 2-3.
See Figure 3-6 for WRSR timing sequence.
TABLE 2-3:
BP1
0
0
1
1
ARRAY PROTECTION
BP0
Array Addresses
Write Protected
0
none
1
upper 1/4
0C00h - 0FFFh
0
upper 1/2
0800h - 0FFFh
1
all
0000h - 0FFFh
DS21158B-page 6
Preliminary
© 1996 Microchip Technology Inc.