DS1923-F5# Maxim Integrated Products, DS1923-F5# Datasheet - Page 23

• Manufacturer Part Number: DS1923-F5#
• Description: IBUTTON TEMP/HUMIDITY LOGGER F5
• Manufacturer: Maxim Integrated Products
• Series: iButton®r

Specifications of DS1923-F5#

• Rohs Information: IButton RoHS Compliance Plan
• Memory Size: 512B
• Memory Type: NVSRAM (Non-Volatile SRAM)
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption

The content of the Mission Start Delay Counter register
tells how many minutes must expire from the time a mis-
sion was started until the first measurement of the mis-
sion takes place (SUTA = 0) or until the device starts
testing the temperature for a temperature alarm (SUTA =
1). The Mission Start Delay register is stored as an
unsigned 24-bit integer number. The maximum delay is
16,777,215min, equivalent to 11,650 days or roughly
31yr. If the start delay is nonzero and the SUTA bit is set
to 1, first the delay must expire before the device starts
testing for temperature alarms to begin logging data.
For a typical mission, the Mission Start Delay is 0. If a
mission is too long for a single DS1923 to store all read-
ings at the selected sample rate, one can use several
devices and set the Mission Start Delay for the second
device to start recording as soon as the memory of the
first device is full, and so on. The RO bit in the Mission
Control register (address 0213h) must be set to 0 to
prevent overwriting of collected data once the data-log
memory is full.
Note: During a mission, there is only read access to this register.
Note: There is only read access to this register.
Note: There is only read access to this register. Note that when both the internal temperature and humidity logging are enabled, the
two log readings are counted as one event in the Mission Samples Counter and Device Samples Counter.
ADDRESS
ADDRESS
ADDRESS
021Ah
021Bh
021Ch
021Dh
0219h
021Eh
0220h
0221h
0222h
0216h
0217h
0218h
Hygrochron Temperature/Humidity Logger
CENT
BIT 7
BIT 7
BIT 7
______________________________________________________________________________________
0
0
0
0
12/24
BIT 6
BIT 6
BIT 6
iButton with 8KB Data-Log Memory
Mission Start Delay
0
0
10 Years
10 Seconds
10 Minutes
20 Hours
AM/PM
BIT 5
BIT 5
BIT 5
0
10 Date
10 Months
10 Hours
BIT 4
BIT 4
BIT 4
Delay Center Byte
Delay High Byte
Delay Low Byte
Mission Start Delay Counter Register Bitmap
Center Byte
High Byte
Low Byte
The Mission Timestamp register indicates the date and time
of the first temperature and humidity sample of the mission.
There is only read access to the Mission Timestamp register.
Depending on settings in the Mission Control register
(address 0213h), the DS1923 logs temperature and/or
humidity in 8-bit or 16-bit format. The description of the
ETL and EHL bit explains where the device stores data
in its data-log memory. The Mission Samples Counter
register together with the starting address and the log-
ging format (8 or 16 bits) provide the information to iden-
tify valid blocks of data that have been gathered during
the current (MIP = 1) or latest mission (MIP = 0). See the
Data-Log Memory Usage section for an illustration. Note
that when SUTA = 1, the Mission Samples Counter does
not increment when the first sample is logged.
The number read from the Mission Samples Counter indi-
cates how often the DS1923 woke up during a mission to
measure temperature and/or humidity. The number for-
mat is 24-bit unsigned integer. The Mission Samples
Counter is reset through the Clear Memory command.
Mission Samples Counter Register Bitmap
BIT 3
BIT 3
BIT 3
Mission Timestamp Register Bitmap
BIT 2
BIT 2
BIT 2
Mission Progress Indicator
Single Seconds
Single Minutes
Single Months
Single Hours
Single Years
Single Date
Mission Timestamp
BIT 1
BIT 1
BIT 1
BIT 0
BIT 0
BIT 0
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