Rainbow Electronics DS28EA00 - Manual (Page 29)

DS28EA00 1-Wire Digital Thermometer with Sequence Detect and PIO
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PIO ACCESS WRITE (SUCCESS)
RST PD Select PIOW <PIO Output data> <PIO Output data> <AAh> <PIO Status Byte>
PIO ACCESS WRITE ( INVALID DATA BYTE )
RST PD Select PIOW <PIO Output data> <invalid data byte> FF loop
The PIO Access Write command is ignored by the device while in Chain ON or Chain DONE state.
CHANGE CHAIN STATE (SUCCESS)
RST PD Select CHAIN <Chain Control Byte> <Chain Control Byte> AA loop
CHANGE CHAIN STATE ( TRANSMISSION ERROR )
RST PD Select CHAIN <Any Byte> < Byte
≠ inverted Previous byte> 00 loop
CHANGE CHAIN STATE ( INVALID CONTROL BYTE )
RST PD Select CHAIN <Invalid Control Byte> <Inverted Previous Byte > xx loop
SEQUENCE DISCOVERY EXAMPLE
RST PD SKIPR CHAIN <5Ah> <A5h> Wait for chain to charge <AAh>
RST PD CDRR <Registration Number> CHAIN <96h> <69h> <AAh>
RST PD CDRR <Registration Number> CHAIN <96h> <69h> <AAh>
RST PD CDRR <8 bytes FFh>
RST PD SKIPR CHAIN <3Ch> <C3h> <AAh>
For the sequence discovery to function properly, the logic state at PIOB (EN\) must not change during the
transmission of the Conditional Read ROM command code, and, if the device responds, must stay at logic 0 until
the entire 64-bit Registration Number is transmitted.
Loop until master sends Reset Pulse
Identify the first device and
put it into Chain DONE state.
Identify the next device and
put it into Chain DONE state.
Repeat this sequence until no
device responds.
No response, all devices have been discovered.
Put all devices into Chain OFF state.
Put all devices into
Chain ON state.