FM22L16
Figure 2. Write-Protect State Machine
For example, the following sequence write-protects addresses from 18000hto 27FFFh(sectors 3 & 4):
Address Data
Read 24555h
Read 3AAAAh
Read 02333h
Read 1CCCCh
Read 000FFh
Read 3EF00h
Write 3AAAAh
Write 1CCCCh
Write 0FF00h
Read 00000h
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18h
E7h
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; bits 3 & 4 = 1
; complement of 18h
; Data is don’t care
; return to Normal Operation
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Rev. 1.0
Mar. 2007
Page 6 of 15