Datasheet

DS28E05 1-Wire EEPROM
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Maxim Integrated │ 10
Read Memory [F0h]
TheReadMemorycommandisusedtoreadthememory.Thecommandneedsa16-bitstartingaddressTA1,TA2.The
parameterbytespecifiestheloweraddressbyte(TA1,T[6:0])wherethereadingbegins.Aftertheparameterbyte,the
mastertransmitsTA2(T[15:8]),whichmustbe00tobevalid.Thereadingcanstartatanyvalidstartingaddressand
continuetroughtheendofthememory.Ifmemorypage7isreadandthemastercontinuesreading,theresultingdata
isFFh.ThemastercanendtheReadMemorycommandatanytimebyissuingaresetpulse.
1-Wire Bus System
The 1-Wire bus is a system that has a single bus master
and one or more slaves. In all instances the DS28E05
is a slave device. The discussion of this bus system is
broken down into three topics: hardware configuration,
transactionsequence,and1-Wiresignaling(signaltypes
and timing). The 1-Wire protocol defines bus transactions
intermsofthebusstateduringspecifictimeslots,which
are initiated on the falling edge of sync pulses from the
bus master.
Hardware Conguration
The1-Wirebushasonlyasinglelinebydefinition;itis
important that each device on the bus be able to drive
itat the appropriate time. To facilitate this, each device
attached to the 1-Wire bus must have open-drain or three-
state outputs. The 1-Wire port of the DS28E05 is open
drain with an internal circuit equivalent to that shown in
Figure7.
Table 4. Parameter Byte Bitmap
Note: The bit marked as 0 must be transmitted as 0 for the parameter byte to be valid.
Figure 7. Hardware Configuration
Read Memory
CommandCode F0h
ParameterByte Starting memory address (Table 4).
Restrictions
None.Thiscommandcanbeissuedatanytime.
ProtocolVariations None.
Error conditions Invalid parameter byte.
CSByte N/A
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
0 TA1
Rx
R
PUP
I
L
V
PUP
BUS MASTER
OPEN-DRAIN
PORT PIN
100
Ω MOSFET
Tx
Rx
Tx
DATA
DS28E05 1-Wire PORT
Rx = RECEIVE
Tx = TRANSMIT