DS1921 datasheet(33/44 Pages) DALLAS

33 / 44 page

DS1921H/Z

33 of 44

CRC-16 HARDWARE DESCRIPTION AND POLYNOMIAL Figure 16

Polynomial = X

+ X

+ 1

STAGE

INPUT DATA

CRC

OUTPUT

Command-Specific 1-Wire Communication Protocol — Legend

Symbol

Description

RST

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"

Command "Read Scratchpad"

CPS

Command "Copy Scratchpad"

Command "Read Memory"

RMC

Command "Read Memory with CRC"

Command "Clear Memory"

Command "Convert Temperature"

Target Address TA1, TA2

TA-E/S

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

<00 to EOP>

Transfer of as many 00h bytes as are needed to reach a memory page boundary

<32 bytes>

Transfer of 32 bytes

<data>

Transfer of an undetermined amount of data

CRC16\

Transfer of an inverted CRC16

FF loop

Indefinite loop where the master reads FFh bytes

AA loop

Indefinite loop where the master reads AAh bytes

00 loop

Indefinite loop where the master reads 00h bytes

DS1921 Datasheet(PDF) 33 Page - Dallas Semiconductor

DS1921 Datasheet(HTML) 33 Page - Dallas Semiconductor

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

Datasheet Download

Link URL