example I2C bus talking to MMA8653FC

[K Rhodes]

I am having a problem talking to a MMA8653FC 3-axis Accelerometer from NXP.

I never see the clock signal generated.

I am using the nRF52 lib, communicating to a nRF5280 chip mounted on a MDBT50Q module from Raytac Corp.

Can someone point me to some example code using the nRF52 talking to any Accelerometer.

[Karl Ylvisaker]

Hi,

I never see the clock signal generated.

Does this mean that you are using an oscilloscope on the SCL pin, and seeing nothing?
If so, could you please share your code? That way I would more easily be able to pinpoint what is not working.

Can someone point me to some example code using the nRF52 talking to any Accelerometer.

Have you seen the TWI sensor example? In this example, it is demonstrated how to setup and communicate between a Nordic SoC and an arbitrary sensor, using TWI.
If you are unable to see anything on your SCL pin, you need to make sure that the initialization and usage is correct.
Do you have a debugger available, so you may step through your code to see what is going on?

Best regards,
Karl

 

[K Rhodes]

The example you sent is using a UART not I2C. Are there any I2C example? 

[Karl Ylvisaker]

Well, yes and no. The example I sent does actually demonstrate how to use TWI ( which is I2C ).
The successful readings from the sensor is sent to the serial port using UART.

So, the UART part is just to visualize the data for you. The data is in fact retrieved from the sensor using TWI.
Please have a closer look at the documentation I linked, or at the examples source code.

Best regards,
Karl

[K Rhodes]

Thanks Karl for getting back to me.

Yes, when I said that I see no SCL signal I was talking about on my oscilloscope. The code that I am running is the example code \example\perpheral\twi_scanner in the nRF5 SDK 16. I did update the pca10056.h file with the correct pin assignment for SLC and SDA.

[Mojo]

Have a look at these sensor drivers https://github.com/IOsonata/IOsonata/tree/master/src/sensors

usage examples : https://github.com/IOsonata/IOsonata/tree/master/exemples/sensor

examples with ble to send sensor data to Thingy App. : https://github.com/IOsonata/IOsonata/tree/master/ARM/Nordic/exemples/BlueIOThingy