Datasheet

DS1921G
Thermochron iButton
26 ______________________________________________________________________________________
DS1921G SETS MIP = 1;
MEMCLR = 0
DS1921G COPIES RTC TO
MISSION TIMESTAMP
DS1921G SETS MIP = 0
DS1921G WAITS
UNTIL NEXT MINUTE
BOUNDARY
DS1921G WAITS
ONE SAMPLE
PERIOD
DS1921G
LOGGING
PROCESS
DS1921G WAITS UNTIL NEXT
MINUTE BOUNDARY
DS1921G COPIES NEW SAMPLE
RATE FROM SCRATCHPAD TO
SAMPLE RATE REGISTER
MIP = 1?
MIP = 1?
Y
N
N
NEW SAMPLE
RATE = 0?
START DELAY
COUNTER = 0?
N
N
N
N
EM = 0?
YN
RO = 1?
N
Y
Y
N
Y
MEMCLR = 1?
Y
DS1921G DECREMENTS
START DELAY COUNTER
Y
MISSION START PROCESS
DS1921G SETS DATA-LOG
ADDRESS = 1000h
DS1921G MEASURES
TEMPERATURE
DS1921G STORES TEMPERATURE
AT DATA-LOG ADDRESS
DS1921G INCREMENTS
DATA-LOG ADDRESS
DS1921G STORES TEMPERATURE
AT DATA-LOG ADDRESS
DS1921G INCREMENTS LOWER
11 BITS OF DATA-LOG ADDRESS
DS1921G UPDATES HISTOGRAM,
DEVICE SAMPLES COUNTER,
MISSION SAMPLES COUNTER
AND ALARM, IF APPLICABLE
MIP = 1?
DATA-LOG
ADDRESS = 1800h?
Y
Y
LOGGING PROCESS
END OF PROCESS
END OF PROCESS
NOTE: THE MISSION START PROCESS IS INVOKED WHEN THE COPY SCRATCHPAD COMMAND IS USED TO SET A NEW SAMPLE RATE BY WRITING TO THE SAMPLE RATE
REGISTER AT ADDRESS 020Dh. ONE MINUTE AFTER THE START DELAY COUNTDOWN IS OVER, THE LOGGING PROCESS BEGINS AND THE MISSION START PROCESS ENDS.
Figure 11. Mission Start and Logging Process