Pmod HYGRO Reference Manual
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Parameter
Value
Units
RH Accuracy
±2
%RH
RH Repeatability
±0.1
%RH
RH Hysteresis
±1
%RH
RH Response Time
15
sec
Temperature Accuracy
±0.2
̊C
Sleep Mode Current Draw
100
nA
3
Interfacing with the Pmod
The Pmod HYGRO communicates with the host board via the
I²C protocol
. By first sending the 7-bit I²C address of
1000000 (0x40) and then a read/write bit (high/low logic level, respectively), followed by the register address of
interest at a maximum clock frequency of 400
kHz, users can both configure and read from the Pmod
HYGRO.
Header J2
on the Pmod HYGRO passes through all of the signals present on the main
Header J1
to allow
for the daisy chaining of multiple I²C compatible modules.
3.1 Configuration Register
The Configuration register (address 0x02) allows users to control the resolution of the temperature and humidity
measurements, change the acquisition mode, enable the heater, and more. A table of the 16-bit register,
recreated from Table 4 in the
HDC1080 datasheet
, is provided below.
Bit Name
Bit Number
Bit Description
Bit Values
Functional Description
RST
[15]
Software reset bit
0
1
Normal Operation, this bit self clears
1
Software Reset
Reserved
[14]
Reserved
0
Reserved, must be 0
HEAT
[13]
Heater
0
1
Heater Disabled
1
Heater Enabled
MODE
[12]
Acquisition Mode
0
Temperature or Humidity is acquired
depending on which register you
choose to read
1
1
Temperature and Humidity are
acquired in sequence, with the
Temperature first
BTST
[11]
Battery Status
0
1
Battery voltage (Vdd) > 2.8V (read
only)
1
Battery voltage (Vdd) < 2.8V (read
only)
TRES
[10]
Temperature
Measurement
Resolution
0
1
14 bit
1
11 bit
HRES
[9:8]
Humidity
Measurement
Resolution
00
1
14 bit
01
11 bit
10
8 bit
Reserved
[7:0]
Reserved
0
Reserved, must be 0
1
This is the default value on power-up or reset.
Table 3. Configuration register description (Address 0x02).