DS1921H/Z
HIERARCHICAL STRUCTURE FOR 1-Wire PROTOCOL Figure 2
1-Wire net
Other
Bus
Devices
Master
DS1921
Command
Level:
Available
Commands:
Cmd. Data Field
Codes: Affected:
Read ROM
33h
55h
F0h
CCh
3Ch
69h
ECh
64-bit Reg. #
64-bit Reg. #
64-bit Reg. #
N/A
OD-Flag
64-bit Reg. #, OD-Flag
Match ROM
Search ROM
Skip ROM
Overdrive Skip
Overdrive Match
Conditional Search
ROM
1-Wire ROM Function
Commands
64-bit Reg. #, Cond. Search settings,
device status
Write Scratchpad
Read Scratchpad
Copy Scratchpad
Read Memory
Read Memory w/CRC
Clear Memory
0Fh
AAh
55h
F0h
A5h
3Ch
256-bit scratchpad, flags
256-bit scratchpad
4096-bit SRAM, registers, flags
All memory
DS1921-Specific
Memory/Control
Function Commands
All memory
Mission Time Stamp, Mission Samples
Counter, Start Delay, Sample
Rate, Alarm Time Stamps and
Durations, Histogram Memory
Memory address 211h
Convert Temperature
44h
64-BIT LASERED ROM Figure 3
MSB
LSB
8-Bit
CRC Code
12-Bit Temperature
Range Code
8-Bit Family
Code (21h)
36-Bit Serial Number
MSB
LSB
MSB
LSB
MSB
LSB MSB LSB
DEVICE
TEMP.
RESOLUTION
TEMP. RANGE CODE
HEX.
RANGE (°C)
EQUIVALENT
(°C)
DS1921H-F5
DS1921Z-F5
+15 to +46
-5 to +26
0.125
0.125
0100
1111
1011
0010
0010
4F2
3B2
0011
4 of 44
DALLAS [ DALLAS SEMICONDUCTOR ]
