DS1921G Maxim, DS1921G Datasheet - Page 23

• Manufacturer Part Number: DS1921G
• Description: The DS1921G Thermochron® iButton® is a rugged, self-sufficient system that measures temperature and records the result in a protected memory section
• Manufacturer: Maxim

Figure 10b. Memory/Control Function Flowchart
FROM FIGURE 10a
TO FIGURE 10a
INCREMENTS
ADDRESS
COUNTER
DS1921G
N
Y
MEMORY ADDRESS = [T15:T0]
MASTER Rx DATA BYTE FROM
______________________________________________________________________________________
TA1 [T7:T0], TA2 [T15:T8]
MEMORY ADDRESS
MASTER Tx RESET?
READ MEMORY?
DS1921G SETS
DS1921G SETS
MASTER Rx "0"
MASTER Rx
EMCLR = 0
MEMORY?
END OF
F0h
Y
N
Y
N
DECISION MADE
DECISION MADE
BY DS1921G
BY MASTER
MASTER Rx
00 BYTE
Y
Y
(1ST PASS); CRC-16 OF DATA
COMMAND, ADDRESS, DATA
FROM MEMORY ADDRESS
TA1 [T7:T0], TA2 [T15:T8]
DS1921G SETS MEMORY
(SUBSEQUENT PASSES)
MASTER Rx DATA BYTE
MASTER Rx CRC-16 OF
ADDRESS = [T15:T0]
MASTER Tx RESET?
READ MEMORY
DS1921G SETS
END OF PAGE?
MASTER Tx
MASTER Tx
EMCLR = 0
WITH CRC
MEMORY?
CRC OK?
END OF
RESET
A5h
Y
N
N
Y
N
Thermochron iButton
N
N
Y
INCREMENTS
COUNTER
ADDRESS
DS1921G
N
TIMESTAMPS AND DURATIONS
DS1921G CLEARS HISTOGRAM
SAMPLES COUNTER, MISSION
START DELAY, SAMPLE RATE
DS1921G CLEARS MISSION
DS1921G CLEARS ALARM
TIMESTAMP, MISSION
MASTER Tx RESET?
CLEAR MEMORY
DS1921G SETS
DS1921G SETS
MEMCLR = 1
EMCLR = 1?
EMCLR = 0
REGISTER
MEMORY
3Ch
Y
Y
Y
N
N
FROM FIGURE 10c
TO FIGURE 10c
23