Datasheet

1 9
Ack by
Slave
Start by
Master
SCL
SDA
Frame 1
7-bit Serial Bus Address Byte
R/W
A2 A0A1A3A4A5A6
D7 D6 D5 D4 D3 D2 D1 D0
1 9
Nack by
Master
Stop by
Master
1 9
D15 D14 D13 D12 D11 D10 D9 D8
Ack by
Master
Frame 4
Data MSB from
Slave
Frame 5
Data LSB from
Slave
1 9
P7 P6 P5 P4 P3 P2 P1 P0
Ack by
Slave
Frame 2
Pointer Register Byte
1 9
Start by
Master
SCL
SDA
Frame 3
7-bit Serial Bus Address Byte
R/W
A2
A0A1
A3A4A5A6
Ack by
Slave
HDC1080
www.ti.com SNAS672A –NOVEMBER 2015–REVISED JANUARY 2016
Programming (continued)
Figure 11. Reading Frame (Configuration Register)
8.5.1.3 Device Measurement Configuration
By default the HDC1080 will first perform a temperature measurement followed by a humidity measurement. On
power-up, the HDC1080 enters a low power sleep mode and is not actively measuring. Use the following steps
to perform a measurement of both temperature and humidity and then retrieve the results:
1. Configure the acquisition parameters in register address 0x02:
(a) Set the acquisition mode to measure both temperature and humidity by setting Bit[12] to 1.
(b) Set the desired temperature measurement resolution:
– Set Bit[10] to 0 for 14 bit resolution.
– Set Bit[10] to 1 for 11 bit resolution.
(c) 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 measurements by executing a pointer write transaction with the address pointer set to 0x00.
Refer to Figure 12.
3. Wait for the measurements to complete, based on the conversion time (refer to Electrical Characteristics
(1)
for the conversion time).
4. Read the output data:
Read the temperature data from register address 0x00, followed by the humidity data from register address
0x01 in a single transaction as shown in Figure 14. A read operation will return a NACK if the contents of the
registers have not been updated as shown in Figure 13.
To perform another acquisition with the same measurement configuration simply repeat steps 2 through 4.
If only a humidity or temperature measurement is desired, the following steps will perform a measurement and
retrieve the result:
1. Configure the acquisition parameters in register address 0x02:
(a) Set the acquisition mode to independently measure temperature or humidity by setting Bit[12] to 0.
(b) For a temperature measurement, set the desired temperature measurement resolution:
– Set Bit[10] to 0 for 14 bit resolution.
– Set Bit[10] to 1 for 11 bit resolution.
(1) Electrical Characteristics Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions
result in very limited self-heating of the device such that TJ = TA. No guarantee of parametric performance is indicated in the electrical
tables under conditions of internal self-heating where TJ > TA. Absolute Maximum Ratings indicate junction temperature limits beyond
which the device may be permanently degraded, either mechanically or electrically.
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