В том то и дело, что сделал по даташиту DS18B20.pdf ("MEMORY FUNCTION EXAMPLE Table 5"):
TX Reset Reset pulse (480-960 μs).
RX Presence Presence pulse.
TX 55h Issue “Match ROM” command.
TX <64-bit ROM code> Issue address for DS18B20.
TX 44h Issue “ Convert T” command.
TX I/O line is held high for at least a period of time greater than tconv by bus master to allow conversion to complete.
TX Reset Reset pulse.
RX Presence Presence pulse.
TX 55h Issue “Match ROM” command.
TX <64-bit ROM code> Issue address for DS18B20.
TX BEh Issue “Read Scratchpad” command.
RX <9 data bytes> Read entire scratchpad plus CRC; the master now
recalculates the CRC of the eight data bytes received
from the scratchpad, compares the CRC calculated and
the CRC read. If they match, the master continues; if
not, this read operation is repeated.
TX Reset Reset pulse.
RX Presence Presence pulse, done.
