Data Sheet

12
www.epluse.com v1.3 / Modification rights reserved
HTE501
5.3 I
2
C Communication
The I²C communication is based on the NXP UM10204 I²C bus specification and user manual
1)
.
The HTE501 supports the modes “standard“ (100 kHz), “fast mode“(400 kHz) and “fast mode plus”
(1 000 kHz).
The sensor works as SLAVE and needs to be queried by a MASTER.
Please consider self-heating due to a low R
PU
when the sensor has to sink the pull-up current. In this case,
the residual voltage on the SCL or SDA pin briefly generates a power loss in the sensor.
Example: 4mA * 0.4V = 1.6mW
5.4 I
2
C Address Pins
The sensor‘s I
2
C base address is 0x40 (without R/ bit). Pins A1...A3 define the I
2
C base address.
PIN 7
PIN6
PIN3
SLAVE
Address
(unshifted)
SLAVE
Address
(with
)
SLAVE
Address
(with R)
A3 A2 A1
R/
bit # 7 6 5 4 3 2 1 0
1 0 0 0 0 0 0 0/1 0x40 0x80 0x81
1 0 0 0 0 0 1 0/1 0x41 0x82 0x83
1 0 0 0 0 1 0 0/1 0x42 0x84 0x85
1 0 0 0 0 1 1 0/1 0x43 0x86 0x87
1 0 0 0 1 0 0 0/1 0x44 0x88 0x89
1 0 0 0 1 0 1 0/1 0x45 0x8A 0x8B
1 0 0 0 1 1 0 0/1 0x46 0x8C 0x8D
1 0 0 0 1 1 1 0/1 0x47 0x8E 0x8F
5.5 HI Pin
The HI pin means “Heater/Invalid” and it indicates that the measurement does not show the real
environmental humidity and temperature conditions:
1. Internal heater on: the internal heater starts a self-heating, and therefore the temperature is higher and
the humidity is lower than the surrounding environmental conditions actually are.
a. Heater ON (command 0x306D)  pin = LOW
b. Heater OFF (command 0x3066)  pin = high-Z
2. Recent measurement was invalid:
a. Recent measurement (temperature or/and humidity) was:
i. valid  pin = high-Z
ii. invalid  pin = LOW
The status of each measurement (valid/invalid) can be read out from the status register 2.
b. During power up until the start-up measurement and calculation is finished
(please refer to Figure 7 in chapter 5.2.)
1) Revision 6, 4 April 2014, download from https://www.nxp.com/docs/en/user-guide/UM10204.pdf.