SI7013-A20 Datasheet, PDF (31/45 Pages) Silicon Laboratories – IC HUMIDITY AND TWO-ZONE TEMPERATURE SENSOR

5.5. Firmware Revision
The internal firmware revision can be read with the following I2C transaction:
Si7013-A20
S
Slave
Address
WA
0x84
A
0xB8
AS
Slave
Address
R A FWREV A NA P
The values in this field are encoded as follows:
0xFF = Firmware revision 1.0
0x20 = Firmware revision 2.0
5.6. Heater
The Si7013 contains an integrated resistive heating element that may be used to raise the temperature of the
sensor. This element can be used to test the sensor, to drive off condensation, or to implement dew-point
measurement when the Si7013 is used in conjunction with a separate temperature sensor such as another Si7013
(the heater will raise the temperature of the internal temperature sensor).
The heater can be activated using HTRE, bit 2 in User Register 1. Turning on the heater will reduce the tendency
of the humidity sensor to accumulate an offset due to "memory" of sustained high humidity conditions. Several
different power levels are available. The various settings are adjusted using User Register 3 and are described in
Table 20.
Table 20. Heater Control Settings
HEATER[3:0] Typical Current
Draw^* (mA)
0000
3.09
0001
9.18
0010
15.24
...
...
0100
27.39
...
...
1000
51.69
...
...
1111
94.20
*Note: Assumes V_DD = 3.3 V.
Rev. 1.1
31