User manual
Pmod HYGRO Reference Manual
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Page 4 of 6
I2CReadMultiple(4); //read four bytes, sending an ACK to the slave after each
byte received and a NACK after the last byte
8. Convert the readings into usable data. Note that the two LSBs (D1 and D0) will always be set to a value of
0. Only the upper 14-bits in each register contains the relevant data
9. Wait at least one full second before initiating another reading to avoid internal heating of the humidity
sensor.
3.4 Pinout Table Diagram
Header J1
Header J2
Jumper Blocks
Pin
Signal
Description
Pin
Signal
Description
Jumper
State
Description
1
NC
Not
Connected
1
NC
Not
Connected
JP1
Both
Enabled
2.2 kΩ resistors
enabled on the SDA
and SCL lines
2
NC
Not
Connected
2
NC
Not
Connected
JP1
Both
Disabled
2.2 kΩ resistors
disabled on the
SDA and SCL lines
3
SCL
Serial Clock
3
SCL
Serial Clock
4
SDA
Serial Data
4
SDA
Serial Data
5
GND
Power Supply
Ground
5
GND
Power Supply
Ground
6
VCC
Power Supply
(3.3V/5V)
6
VCC
Power Supply
(3.3V/5V)
The Pmod HYGRO is an ideal Pmod to use in long term humidity test application. As a very low power Pmod
between measurements, long term data to measure humidity changes in an environment can easily be collected.
Any external power applied to the Pmod HYGRO must be within 2.7V and 5.5V to ensure that the on-board chips
operate correctly; however, it is recommended that Pmod is operated at 3.3V.
3.5 Timing Diagram
A sample timing diagram for writing to and reading from the Pmod HYGRO taken from the HDC1080 datasheet are
provided below: