Datasheet

DS1921G
Thermochron iButton
10 ______________________________________________________________________________________
32-BYTE INTERMEDIATE STORAGE SCRATCHPAD
ADDRESS
0000h to 01FFh GENERAL-PURPOSE SRAM (16 PAGES) PAGES 0 to 15
0200h to 021Fh 32-BYTE REGISTER PAGE PAGE 16
0220h to 027Fh ALARM TIMESTAMPS AND DURATIONS PAGES 17 to 19
0280h to 07FFh (RESERVED FOR FUTURE EXTENSIONS) PAGES 20 to 63
0800h to 087Fh TEMPERATURE HISTOGRAM MEMORY PAGES 64 to 67
0880h to 0FFFh (RESERVED FOR FUTURE EXTENSIONS) PAGES 68 to 127
1000h to 17FFh DATA-LOG MEMORY (64 PAGES) PAGES128 to 191
1800h to 1FFFh (RESERVED FOR FUTURE EXTENSIONS) PAGES 192 to 255
Figure 5. Memory Map
ADDRESS BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 FUNCTION ACCESS*
0200h 0 10 Seconds Single Seconds
0201h 0 10 Minutes Single Minutes
0202h 0 12/24
20 Hour
AM/PM
10 Hour Single Hours
0203h 0 0 0 0 0 Day of Week
0204h 0 0 10 Date Single Date
0205h CENT 0 0
10
Months
Single Months
0206h 10 Years Single Years
RTC
Registers
R/W R/W**
0207h MS 10 Seconds Alarm Single Seconds Alarm
0208h MM 10 Minutes Alarm Single Minutes Alarm
0209h MH 12/24
20 Hour
AM/PM
Alarm
10 Hour
Alarm
Single Hours Alarm
020Ah MD 0 0 0 0 Day of Week Alarm
RTC Alarm
Registers
R/W R/W**
020Bh Temperature Low Alarm Threshold
020Ch Temperature High Alarm Threshold
Temperature
Alarms
R/W R/W**
020Dh Number of Minutes Between Temperature Conversions Sample Rate R/W R**
020Eh EOSC EMCLR 0 EM RO TLS THS TAS Control R/W R/W**
020Fh (No function, reads 00h) — R R**
Figure 6. Register Pages Map
* The left entry in the ACCESS column is valid between missions. The right entry shows the applicable access mode while a
mission is in progress.
** While a mission is in progress, these addresses can be read. The first attempt to write to these registers (even read-only
ones), however, ends the mission and overwrites selected writable registers.