DS1921H_11 MAXIM [Maxim Integrated Products], DS1921H_11 Datasheet - Page 4

• Manufacturer Part Number: DS1921H_11
• Description: High-Resolution Thermochron iButton
• Manufacturer: MAXIM [Maxim Integrated Products]

The shift register bits are initialized to 0. Then starting with the least significant bit of the family code,
one bit at a time is shifted in. After the eighth bit of the family code has been entered, then the serial
number followed by the temperature range code is entered. After the range code has been entered, the
shift register contains the CRC value. Shifting in the eight bits of CRC returns the shift register to all 0s.
HIERARCHICAL STRUCTURE FOR 1-Wire PROTOCOL Figure 2
64-BIT LASERED ROM Figure 3
MSB
MSB
DEVICE
DS1921H-F5
DS1921Z-F5
CRC Code
Master
Command
Level:
8-Bit
Bus
1-Wire ROM Function
Function Commands
LSB
DS1921-Specific
Memory/Control
Commands
RANGE (°C)
+15 to +46
-5 to +26
MSB
TEMP.
12-Bit Temperature
Range Code
1-Wire net
RESOLUTION
DS1921
Available
Commands:
Read ROM
Match ROM
Search ROM
Skip ROM
Overdrive Skip
Overdrive Match
Conditional Search
Write Scratchpad
Read Scratchpad
Copy Scratchpad
Read Memory
Read Memory w/CRC
Clear Memory
Convert Temperature
0.125
0.125
(°C)
LSB
ROM
MSB
4 of 45
0100
0011
36-Bit Serial Number
TEMP. RANGE CODE
Codes:
Cmd.
CCh
ECh
AAh
3Ch
A5h
3Ch
33h
55h
F0h
69h
0Fh
55h
F0h
44h
1111
1011
Devices
Other
Data Field
Affected:
64-bit Reg. #
64-bit Reg. #
64-bit Reg. #
N/A
OD-Flag
64-bit Reg. #, OD-Flag
64-bit Reg. #, Cond. Search settings,
256-bit scratchpad, flags
256-bit scratchpad
4096-bit SRAM, registers, flags
All memory
All memory
Mission Time Stamp, Mission Samples
Memory address 211h
0010
0010
LSB
device status
Counter, Start Delay, Sample
Rate, Alarm Time Stamps and
Durations, Histogram Memory
MSB
EQUIVALENT
8-Bit Family
Code (21h)
HEX.
3B2
4F2
LSB
LSB