Datasheet

DS28E05 1-Wire EEPROM
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Write Memory [55h]
The Write Memory command is used to program one or more contiguous 2-byte segments of a memory page. This com-
mand is applicable only to memory locations that are not write protected. The parameter byte specifies the page and
segmentnumberwherethewritingbegins.ThenewsegmentdataistransmittedinthesequenceB0,B1.Table 2 shows
the how these bytes map to the addressed memory page. The command flow allows writing one or multiple adjacent
segmentswithinapage.Tosafeguardagainsttransmissionerrors,theDS28E05supportsread-after-writeverification.
Incaseofdataerror,themasterabortsthecommandbyissuinga1-Wirereset.TostartthetransfertoEEPROMthe
mastermusttransmitareleasebyte(FFh).Aftertheprogrammingtimeisover,theDS28E05transmitsaCSbyte.Ifa
pageisinEPROMemulationmode,thenewsegmentdataisthebitwiseANDofthesegmentdatainmemoryandthe
new data provided with the command.
Bits 6:4: Memory Page Selection (PAGE #).
Thesebitsspecifythememorypagethatistobewrittento.Validmemory
page numbers are 000b (page 0) to 111b (page 7).
Bits 3:1: Starting Segment Selection (SEG #). These bits specify the location within the selected memory page where
thewritingbegins.Forpages0to6validsegmentnumbersare000b(startofmemorypage)to111b(lastsegmentof
memorypage).Validsegmentnumbersforpage7are000b,001b,and010b.
Table 3. Parameter Byte Bitmap
Note: The bits marked as 0 must be transmitted as 0 for the parameter byte to be valid.
Write Memory
CommandCode 55h
ParameterByte Targetpageselection,startingsegmentnumber(Table3).
Restrictions The memory page must not be write protected.
ProtocolVariations
Writing within a page.
Writing through the end of the page.
Error conditions
Invalid parameter byte.
The memory page is write protected.
CSByte
AAh=success.
33h=Thecommandfailedbecausethepageiswriteprotected.
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
0
PAGE# SEG# 0