nRF52832 SPI tx rx

[Minseo]

Hi

I'm developing nRF52832.

I have a question about SPI communication.(\nRF5_SDK_17.0.0\examples\peripheral\spi I don't understand, so I ask questions.)

I want to read sensor data through SPI communication, but I don't know how to separate Tx and Rx into nrf_drv_spi_transfer.

Example.

1-1. If I want to read the 0x00 register address, is it right to set it up like below?

1-2. When I read the 0x00 register address, do I have to read the register address + 0x00?

2-1. Is this the right way to use data through SPI?

Thank you.

[Sigurd Hellesvik]

Hi Minseo

1-1. If I want to read the 0x00 register address, is it right to set it up like below?

Sensors use different ways to read registers. The datasheet of your sensor should explain how to do this.

In the SPI Peripheral sample you are using, the spi_event_handler is called after messages are received. You must wait until this is called before reading the m_rx_buf to read your data.

To ensure that SPI is sending data on the lines, I recommend to use an oscilloscope or logic analyzer to probe the SPI lines. This is also useful to get insight into the workings of SPI.
And it can be used to verify that the data sent on SPI is correctly formatted.

Regards,
Sigurd Hellesvik

[Minseo]

Thank you so much for answering.

Is there no problem with the code?

[Sigurd Hellesvik]

Hi

Also for nrf_drv_spi_transfer:

The first buffer and length is the data you send, then the second buffer and length is the one you receive.

In other words, the transfer function will be called once for both TX and RX.

Then when the spi_event_handler is called , you can read data from your RX register,

So to read the WHOAMI register from your sensor, my guess is that you can use our SPI example and change the following two things:

Change initialization to match your sensor.

Change the TEST_STRING "nordic" to TEST_STRING [1,0,0,0,0,0,0,0]  (1 for read and register address is 0)

For more info on our SPI master driver, see our SPI master documentation.

Does this work for you?

Regards,
Sigurd Hellesvik

[Minseo]

Hi 

I tested <InstallFolder>\examples\peripheral\spi 

The module I'm using now is a module that I made separately by purchasing an nRF52832 MCU.

So I don't know if I can get Rx properly through the example above.

I couldn't check the Rx_buffer, but I could check that the event_handler was working properly.

Thank you

 

[Sigurd Hellesvik]

Hi

If this is the case, I am guessing that there is no data on the MISO line?
Could you verify this by using a oscilloscope or logic analyzer?

How have you connected the pins of the sensor?

Regards,
Sigurd Hellesvik

[Minseo]

Do I need to use nRF DK to use <InstallFolder>\examples\peripheral\spi example?

I don't use nRF52832 DK, so I don't think the MISO line has data. Is that right?

Thank you

[Sigurd Hellesvik]

Hi

I do not think I understand what you mean.

You should be able to use the spi driver with any of our nRF52 microcontrollers.
If you want the nRF to read data from your sensor, you need to connect it to the sensor.

Regards,
Sigurd Hellesvik