SHT25 interface with nordic

[Mr.NCK]

Hi,

I am Using nrf52832DK and SHT25 breakout board. I can't able to read a device address using "TWI Scanner". But, I can able to scan the sht25 device address by Arduino I2c scanner.

I need your help to make work nordic's TWI Scanner for the sht25 breakout board or suggest me the code for the proper interface of sht25 with nrf52832.

[awneil]

Mr.NCK said:

I am Using nrf52832DK and SHT25 breakout board

What "breakout board" are you using?

Show a schematic of how you have connected them together.

Have you checked basics - like pullups?

Have you checked against the datasheet: 

www.sensirion.com/.../Sensirion_Humidity_Sensors_SHT25_Datasheet.pdf

Have you used an oscilloscope to see what's actually happening on the wires?

See: https://devzone.nordicsemi.com/f/nordic-q-a/72492/error-in-establishing-a-connection-between-nrf52840-dk-board-and-sht21-sensor-using-twi-module

[Mr.NCK]

thanks 

1) https://www.evelta.com/evelta-sht25-i2c-temperature-and-humidity-sensor/

2) I have just connected the SCL and SDA pin of the breakout board with nrf52 dk pin 27 And 26

3) that is Breakout right??

4) kindly guide me on what are the things. I need to check

5) I don't have oscilloscope

[awneil]

Please post a complete schematic of your setup - trying to describe it in words really doesn't help.

Mr.NCK said:

I have just connected the SCL and SDA pin of the breakout board with nrf52 dk pin 27 And 26

That won't work - you also need GND and power.

Is your code correctly configured to use those DK pins?

Are you sure that nothing else on the DK is using those pins?

Mr.NCK said:

I don't have oscilloscope

Being able to see what's happening on the wires is key for this kind of project.

You can get cheap logic analysers on ebay for ~ $10

[DD_]

Sensor breakout pin SDA to nRF52DK 26th pin
SCL to 27th pin
Vdd to 3.3V
sensor gnd to nRF gnd. 

   Try to understand our problem first. Same this connection I2C scanner code works for Arduino. 
Same setup with nRF52 DK is not working. Hardware connection has no problem. In firmware code also pca board file changes made according to our hardware connection. I suspect issue with example firmware code. Whether any library needed for sht sensor?  Kindly look into this direction and help us regarding.

[awneil]

DD_ said:

Hardware connection has no problem

The fact that the TWI scanner does not detect the Slave rather suggests that there is a hardware problem.

Again:

awneil said:

Is your code correctly configured to use those DK pins?

Are you sure that nothing else on the DK is using those pins?

And:

awneil said:

Have you checked basics - like pullups?

[Mr.NCK]

Yes, our code was correctly configured with DK pins

yes, we didn't connect anything on those pins

Is this a breakout board right so manufacturer provides the pullups

[awneil]

Mr.NCK said:

we didn't connect anything on those pins

That wasn't the question.

You need to check that there isn't anything on the DK itself that is using those pins.

Mr.NCK said:

Is this a breakout board right so manufacturer provides the pullups

You can't just assume that - what does its documentation tell you?

[DD_]

See I am once again explaining you clearly. First understand our problem. 
SHT20 break out board ( Which will have pull up )
When I am working with arduino there is no problem sht20 works perfectly.
But when I use nRF52 DK it is not working. Those pins in nRF52 is only connected with sht 20 sensor and we are also defining that in firmware board file. 
SHT20 is not detecting only with nRF52 DK. 
Please have a clear understand of our problem then explain and give solution. 




If it's sht20 issue then it should not worked with arduino.
Is there any other way to read sht20 with nRF52 in firmware wise.
If you have any idea regarding tell us. 

[Karl Ylvisaker]

Hello,

DD_ said:

SHT20 break out board ( Which will have pull up )

I will have to reiterate what @awneil has already asked here - how do you know that the SHT20 breakout board / module provide the pullups? You may not just assume.
Do you have a link to the specific module or breakout board you are using, or specifically to the user guide / data sheet of the module?

DD_ said:

When I am working with arduino there is no problem sht20 works perfectly.
But when I use nRF52 DK it is not working.

The Arduino might be providing the pullups here. In which case, the nRF needs to be configured to do the same in order for the TWI communication to work. Again, as @awneil has already mentioned - the fact that the example is unable to find the sensor indicates that there is a hardware problem.

DD_ said:

Those pins in nRF52 is only connected with sht 20 sensor and we are also defining that in firmware board file. 

Would you mind sharing the code section where you setup and configure the TWI peripheral?
It would also be helpful to see the changes you have made to the boardfile. 

DD_ said:

If it's sht20 issue then it should not worked with arduino.

This could for example happen if the sensor does not provide pullups but the Arduino enables pullsups behind the scenes. We will know more about this when we get to see the modules / breakoutboards user manual or data sheet.

Looking forward to resolving this issue together.

Best regards,
Karl

[Mr.NCK]

Online Mr.NCK 20 hours ago

Hi Karl

      We have just use the nordic  TWI scanner we didn't change anything in code only change the pins and we didn't have the breakout board datasheet. We have only the Sht25 SOS datasheet

Thank you