Datasheet

1 9
Start by
Master
SCL
SDA
Frame 3
7-bit Serial Bus Address Byte
R/W
A2
A0A1
A3A4A5A6
Nack by
Slave
1 9
Ack by
Slave
Start by
Master
SCL
SDA
Frame 1
7-bit Serial Bus Address Byte
R/W
A2
A0A1
A3A4A5A6
1 9
P7 P6 P5 P4 P3 P2 P1 P0
Ack by
Slave
Frame 2
Pointer Register Byte
HDC1080
SNAS672A –NOVEMBER 2015–REVISED JANUARY 2016 www.ti.com
Programming (continued)
(c) For a humidity measurement, set the desired humidity measurement resolution:
– Set Bit[9:8] to 00 for 14 bit resolution.
– Set Bit[9:8] to 01 for 11 bit resolution.
– Set Bit[9:8] to 10 for 8 bit resolution.
2. Trigger the measurement by executing a pointer write transaction. Refer to Figure 12
– Set the address pointer to 0x00 for a temperature measurement.
– Set the address pointer to 0x01 for a humidity measurement.
3. Wait for the measurement to complete, based on the conversion time (refer to Electrical Characteristics
(1)
for
the conversion time).
4. Read the output data:
Retrieve the completed measurement result from register address 0x00 or 0x01, as appropriate, as shown in
Figure 11. A read operation will return a NACK if the measurement result is not yet available, as shown in
Figure 13.
To perform another acquisition with the same measurement configuration repeat steps 2 through 4.
It is possible to read the output registers (addresses 0x00 and 0x01) during a Temperature or Relative Humidity
measurement without affecting any ongoing measurement. Note that a write to address 0x00 or 0x01 while a
measurement is ongoing will abort the ongoing measurement.
Figure 12. Trigger Humidity/Temperature Measurement
Figure 13. Read Humidity/Temperature Measurement (Data Not Ready)
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