DS1921H/Z
CRC-16 HARDWARE DESCRIPTION AND POLYNOMIAL Figure 16
Polynomial = X16 + X15 + X2 + 1
1st
2nd
3rd
4th
5th
6th
7th
8th
STAGE STAGE
STAGE STAGE STAGE STAGE STAGE STAGE
X0
X1
X2
X3
X4
X5
X6
X7
9th
10th
11th
12th
13th
14th
15th
16th
STAGE
STAGE STAGE STAGE STAGE STAGE STAGE STAGE
X8
X9 X10 X11 X12 X13 X14
X15 X16
CRC
OUTPUT
INPUT DATA
Command-Specific 1-Wire Communication Protocol — Legend
Symbol
Description
RST
PD
1-Wire Reset Pulse generated by master
1-Wire Presence Pulse generated by slave
Select
Command and data to satisfy the ROM function protocol (Skip ROM, Search ROM, etc.)
Command "Write Scratchpad"
WS
RS
Command "Read Scratchpad"
CPS
Command "Copy Scratchpad"
RM
Command "Read Memory"
RMC
Command "Read Memory with CRC"
CM
Command "Clear Memory"
CT
Command "Convert Temperature"
TA
Target Address TA1, TA2
TA-E/S
<data to EOS>
<data to EOP>
<data to EOM>
<00 to EOP>
<32 bytes>
<data>
CRC16\
FF loop
AA loop
00 loop
Target Address TA1, TA2 with E/S byte
Transfer of as many data bytes as are needed to reach the scratchpad offset 1Fh
Transfer of as many data bytes as are needed to reach the end of a memory page
Transfer of as many data bytes as are needed to reach the end of the datalog memory
Transfer of as many 00h bytes as are needed to reach a memory page boundary
Transfer of 32 bytes
Transfer of an undetermined amount of data
Transfer of an inverted CRC16
Indefinite loop where the master reads FFh bytes
Indefinite loop where the master reads AAh bytes
Indefinite loop where the master reads 00h bytes
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DALLAS [ DALLAS SEMICONDUCTOR ]
