Code hangs when using SPI3

[Madhukeshwar]

we are using SPI3 in nrf52840 with nrf SDK 16.0

we are using this as below

1. SPI3 init -polling mode  

2. SPI3 unint

3. SPI3 init - DMA mode

4. SPI3 unint 

5. SPI3 init -polling mode

6. SPI3 unit

 

The code gets hanged when we write through SPI3 after SPI3 is intialized in polling mode (STEP 5) in above steps 

Can anyone help us in identifying the reason for the hang? 

Thanks in advance,

 

 

Madhukeshwar P

[Edvin]

Ok, so on what function does it hang? Is it waiting in a while loop? Or is it some function that doesn't return?

Are you checking the return values for your SPI calls? Does any of the functions return != 0 when the issue occurs?

BR,
Edvin

[Madhukeshwar]

Hi,

the code hangs in  the below line
while (!nrf_spim_event_check(p_spim, NRF_SPIM_EVENT_END)){} in the file nrfx_spim.c

[Edvin]

And do you see the callstack that brought it there? It looks like it is waiting for the end of some transaction. Have you tried sending it an SPI message, just to see if it is possible to "kick it" out of that state? Not as a solution, but for debugging purposes.

Best regards,

Edvin

[Edvin]

And is there any way for me to reproduce what you are seeing? Do you need to use some external device (SPI device)? Or can you do it just using a DK?

[Madhukeshwar]

Edvin said:

And do you see the callstack that brought it there?

yeah,
 

I have attached the screenshot of the call stack. 

I have checked status of SPI Un-initialization and initialization with the error code it returns. It returned NRF_SUCCESS but the issue still exist.

Edvin said:

Have you tried sending it an SPI message,

yeah. This issue is occurring when we send an SPI message i.e. in spim_xfer function it is getting stuck. The issue is occurring at the same location. but not every time. out of 12 hrs. it can occur up to 4times. 

Edvin said:

Do you need to use some external device (SPI device)?

Yeah, we need to use some external device. you can tell us what need to checked. will check that and update you.  

[Edvin]

Madhukeshwar said:

Yeah, we need to use some external device. you can tell us what need to checked

I suspected that. Is there a chance you can try to check if you are able to reproduce if you use another DK as the SPIS? (SDK\examples\peripheral\spis)

Can you grab another screenshot of the issue and expand the view of the callstack? 

Actually, it looks a bit weird:

What sort of transaction is this? Are you trying to read or write? Because the TX buffer has a length of 0x00, and the RX buffer is located in 0x00000000, but I can't see it's length. So either it means that you are trying to send a message with length 0, or you are trying to receive a message and store it in a buffer located at 0x00000000 (which will cause your device to crash if it was actually stored there, but I guess it is a NULL pointer, because this is a TX transaction, and not an RX or a two way transaction). 

So if you could expand the callstack to show more than just two lines, and try to do some research as to what kind of transaction that is ongoing. Why does it try to send a message with length 0?

BR,

Edvin

[Madhukeshwar]

Edvin said:

What sort of transaction is this? Are you trying to read or write?

We are trying to write with length 2. I have checked by logging. 

//logs printed to check tx_buffer_length
<info> app: p_spi_instant     5DB38
<info> app: p_tx_buffer       2002CBE2
<info> app: tx_buffer_length  2
<info> app: p_rx_buffer       0
<info> app: rx_buffer_length  0

Edvin said:

Why does it try to send a message with length 0?

I am not getting in the call stack why it is showing length as 0.
In the call stack, sometimes TX buffer length is zero. sometimes it has some value. but the issue occurred at the same location each time.

I have taken the multiple screenshots whenever the issue got reproduced. I have attached below.

[Edvin]

What sort of SPI device are you using? Is it possible (for you or me) to write a dummy SPIS device running on another DK that can be used to reproduce the issue? What sort of SPIS commands does it need to respond to? Is it possible to provide a set?

BR,
Edvin