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

[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

[Madhukeshwar]

Edvin said:

What sort of SPI device are you using?

we are using accelerometer. 

Edvin said:

s it possible (for you or me) to write a dummy SPIS device running on another DK that can be used to reproduce the issue?

I am trying to reproduce the issue. 

I found out that NRF_SPIM_EVENT_ENDTX is not getting generated and so the NRF_SPIM_EVENT_END  event. 
what could be the possible reason for NRF_SPIM_EVENT_ENDTX to not get generated?

[Edvin]

What accelerometer? I have a couple laying around. 

Madhukeshwar said:

what could be the possible reason for NRF_SPIM_EVENT_ENDTX to not get generated?

well, I haven't seen any of your code yet, so difficult to say. But I would say that if you didn't actually send an SPI command, but queued it up, that may lead to these kinds of deadlocks. 

However, this also looks like a possible suspect:
https://docs.nordicsemi.com/bundle/errata_nRF52840_Rev3/page/ERR/nRF52840/Rev3/latest/anomaly_840_193.html#anomaly_840_193

The workaround for this errata would either be to make sure that the transmission is completed before you uninit/suspend it, or you can use a timer or something to detect that a certain amount of time has passed without it returning, and power cycle the SPIM3 using the snippet in the errata documentation.

BR,
Edvin

[Madhukeshwar]

Edvin said:

What accelerometer? I have a couple laying around. 

we are using adxl355.

Edvin said:

I haven't seen any of your code yet, so difficult to say.

Our project is too huge. we are trying to reproduce it in another project. we aren't able to reproduce the issue in another project. 

Edvin said:

docs.nordicsemi.com/.../anomaly_840_193.html

We are not using TASK_SUSPEND. this wont be the possible suspect.

Edvin said:

you can use a timer or something to detect that a certain amount of time has passed without it returning, and power cycle the SPIM3 using the snippet in the errata documentation.

After executing this code snippet it is again returning to that while loop.
Even I tried to abort the spi transfer, after executing this abort function it is returning to while loop only. it is coming out of while loop only when the device resets. 

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