Data Sheet

ManualsBrandsSeeedStudio ManualsElectronic Experimentation PartsSeeedStudio Grove I2C High Accuracy Temperature and Humidity Sensor (SHT35)

Datasheet SHT3x-DIS

www.sensirion.com May 2018- Version 5 12/22

Command

Hex Code

Break

0x3093

Table 13 Break command (Clear blocks are controlled by

the microcontroller, grey blocks by the sensor).

4.9 Reset

A system reset of the SHT3x-DIS can be generated

externally by issuing a command (soft reset) or by

sending a pulse to the dedicated reset pin (nReset pin).

Additionally, a system reset is generated internally

during power-up. During the reset procedure the sensor

will not process commands.

In order to achieve a full reset of the sensor without

removing the power supply, it is recommended to use the

nRESET pin of the SHT3x-DIS.

Interface Reset

If communication with the device is lost, the following

signal sequence will reset the serial interface: While

leaving SDA high, toggle SCL nine or more times. This

must be followed by a Transmission Start sequence

preceding the next command. This sequence resets the

interface only. The status register preserves its content.

Soft Reset / Re-Initialization

The SHT3x-DIS provides a soft reset mechanism that

forces the system into a well-defined state without

removing the power supply. When the system is in idle

state the soft reset command can be sent to the SHT3x-

DIS. This triggers the sensor to reset its system

controller and reloads calibration data from the memory.

In order to start the soft reset procedure the command

as shown in Table 14 should be sent.

It is worth noting that the sensor reloads calibration data

prior to every measurement by default.

Command

Hex Code

Soft Reset

0x30A2

Table 14 Soft reset command (Clear blocks are controlled

by the microcontroller, grey blocks by the sensor).

Reset through General Call

Additionally, a reset of the sensor can also be generated

using the “general call” mode according to I2C-bus

specification

. This generates a reset which is

functionally identical to using the nReset pin. It is

important to understand that a reset generated in this

way is not device specific. All devices on the same I2C

bus that support the general call mode will perform a

reset. Additionally, this command only works when the

sensor is able to process I2C commands. The

appropriate command consists of two bytes and is

shown in Table 15.

Command

Code

Address byte

0x00

Second byte

0x06

Reset command using the

general call address

0x0006

Table 15 Reset through the general call address (Clear

blocks are controlled by the microcontroller, grey blocks by

the sensor).

Reset through the nReset Pin

Pulling the nReset pin low (see Table 7) generates a

reset similar to a hard reset. The nReset pin is internally

connected to VDD through a pull-up resistor and hence

active low. The nReset pin has to be pulled low for a

minimum of 1 µs to generate a reset of the sensor.

Hard Reset

A hard reset is achieved by switching the supply voltage

to the VDD Pin off and then on again. In order to prevent

powering the sensor over the ESD diodes, the voltage to

pins 1 (SDA), 4 (SCL) and 2 (ADDR) also needs to be

removed.

4.10 Heater

The SHT3x is equipped with an internal heater, which

is meant for plausibility checking only. The temperature

increase achieved by the heater depends on various

parameters and lies in the range of a few degrees

centigrade. It can be switched on and off by command,

see table below. The status is listed in the status register.

After a reset the heater is disabled (default condition).

ACK

General Call Address

1 2 3 4 5 6 7 8 9

ACK

Reset Command

1 2 3 4 5 6 7 8 9

General Call 1

byte

General Call 2

byte