FM20L08_07 RAMTRON [Ramtron International Corporation], FM20L08_07 Datasheet - Page 6

• Manufacturer Part Number: FM20L08_07
• Description: 1Mbit Bytewide FRAM Memory - Industrial Temp.
• Manufacturer: RAMTRON [Ramtron International Corporation]

For example, the following sequence write-protects addresses from 00000h to 07FFFh and 10000h to 13FFFh
(sectors 0, 1 & 4):
Rev. 1.72
May 2007
Read
Read
Read
Read
Read
Read
Write 1AAAAh
Write 1CCCCh
Write 0FF00h
Read
Address
05555h
1AAAAh
03333h
1CCCCh
100FFh
0FF00h
00000h
Normal Memory
Read 100FFh?
Read 05555h?
Read 03333h?
Read 0FF00?
1CCCCh?
Operation
1AAAAh?
Read
Read
Sequence Detector
y
y
y
y
y
y
Data
n
n
n
n
n
n
13h
Ech
-
-
-
-
-
-
-
-
Figure 2. Write-Protect State Machine
Any other
operation
; bits 0, 1, 4 = 1
; complement of 13h
; Data is don’t care
; return to Normal Operation
n
n
Change Write Protect
Enter new write
Hold Data Byte
protect settings
Write 1CCCC?
Write 1AAAA?
Complement?
Write 0FF00
Read 00000
Settings
Data
y
y
y
y
n
Read Write Protect
Drive write protect
Write 1CCCC?
Read 1AAAA
Read 00000
data out
Settings
y
FM20L08 - Industrial Temp.
n
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