DS1923-F5# Maxim Integrated Products, DS1923-F5# Datasheet - Page 20

• 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

Hygrochron Temperature/Humidity Logger
iButton with 8KB Data-Log Memory
The DS1923 has two Temperature Alarm Threshold
registers (address 0208h, 0209h) to store values that
determine whether a critical temperature has been
reached. A temperature alarm is generated if the
device measures an alarming temperature and the
alarm signaling is enabled. The bits ETLA and ETHA
that enable the temperature alarm are located in the
Temperature Sensor Control register. The temperature
alarm flags TLF and THF are found in the Alarm Status
register at address 0214h.
Bit 1: Enable Temperature High Alarm (ETHA). This
bit controls whether, during a mission, the temperature
high alarm flag (THF) can be set, if a temperature con-
version results in a value equal to or higher than the
value in the Temperature High Alarm Threshold register.
If ETHA is 1, temperature high alarms are enabled. If
ETHA is 0, temperature high alarms are not generated.
Bit 0: Enable Temperature Low Alarm (ETLA). This
bit controls whether, during a mission, the temperature
low alarm flag (TLF) can be set, if a temperature con-
version results in a value equal to or lower than the
value in the Temperature Low Alarm Threshold register.
If ETLA is 1, temperature low alarms are enabled. If
ETLA is 0, temperature low alarms are not generated.
The DS1923 has two Humidity Alarm Threshold regis-
ters (address 020Ah, 020Bh) to store values that deter-
mine whether humidity readings can generate an
alarm. Such an alarm is generated if the humidity data
read from the sensor qualifies for an alarm and the
Note: During a mission, there is only read access to this register. Bits 2 to 7 have no function. They always read 0 and cannot be written to 1.
Note: During a mission, there is only read access to this register. Bits 2 to 7 have no function. They always read 1 and cannot be written to 0.
Note: During a mission, there is only read access to this register. Bits 2 to 7 have no function. They always read 0 and cannot be written to 1.
20
ADDRESS
ADDRESS
ADDRESS
0212h
0211h
0210h
______________________________________________________________________________________
BIT 7
BIT 7
BIT 7
0
1
0
Temperature Sensor Alarm
BIT 6
BIT 6
BIT 6
0
1
0
Humidity Alarm
BIT 5
BIT 5
BIT 5
0
1
0
BIT 4
BIT 4
BIT 4
0
Temperature Sensor Control Register Bitmap
1
0
alarm signaling is enabled. The bits EHLA and EHHA
that enable the humidity alarm are located in the
Humidity Sensor Control register. The corresponding
alarm flags HLF and HHF are found in the Alarm Status
register at address 0214h.
Bit 1: Enable Humidity High Alarm (EHHA). This bit
controls whether, during a mission, the humidity high
alarm flag (HHF) can be set, if a value from the humidi-
ty sensor is equal to or higher than the value in the
Humidity High Alarm Threshold register. If EHHA is 1,
humidity high alarms are enabled. If EHHA is 0, humidi-
ty high alarms are not generated.
Bit 0: Enable Humidity Low Alarm (EHLA). This bit
controls whether, during a mission, the humidity low
alarm flag (HLF) can be set, if a value from the humidity
sensor is equal to or lower than the value in the
Humidity Low Alarm Threshold register. If EHLA is 1,
humidity low alarms are enabled. If EHLA is 0, humidity
low alarms are not generated.
To minimize the power consumption of a DS1923, the
RTC oscillator should be turned off when the device is
not in use. The oscillator on/off bit is located in the RTC
Control register. This register also includes the EHSS
bit, which determines whether the sample rate is speci-
fied in seconds or minutes.
Bit 1: Enable High-Speed Sample (EHSS). This bit
controls the speed of the sample rate counter. When set
to logic 0, the sample rate is specified in minutes. When
set to logic 1, the sample rate is specified in seconds.
Humidity Sensor Control Register Bitmap
BIT 3
BIT 3
BIT 3
0
1
0
RTC Control Register Bitmap
BIT 2
BIT 2
BIT 2
0
1
0
EHSS
EHHA
BIT 1
BIT 1
ETHA
BIT 1
RTC Control
EOSC
BIT 0
EHLA
BIT 0
ETLA
BIT 0