SAADC callback never called with Softdevice

[f.albu]

Hello, I'm having trouble to understand why the saadc buffer is not being filled.

I had already tested this functionality without the softdevice, and everything worked fine but now, with the softdevice,

I found that the "saadc_callback" function is not called at any time. 
I tried to follow some clues after reading several posts here on the blog on this subject, but they did not lead me to a solution.

Tested items:
Modify saadc to continuous mode.
Modify the saadc interrupt priority.


The timer for the PPI ist the TIMER1

Thanks

[Karl Ylvisaker]

Hello,

I'm having trouble to understand why the saadc buffer is not being filled.

Is the SAADC generating any errors, or is it initializing and starting successfully?

I had already tested this functionality without the softdevice, and everything worked fine but now, with the softdevice,

By this, do you mean that the difference is when you enable the SoftDevice? Could you elaborate on how you included and enabled the SoftDevice?

Tested items:
Modify saadc to continuous mode.
Modify the saadc interrupt priority.

Could you share the code where you configure and start the sampling?
Please use the "insert -> Code" option when doing so.

The timer for the PPI ist the TIMER1

Do you mean that the PPI timer IS or ISNT timer1?
Timer0 is the one used by the SoftDevice.

Looking forward to solving this issue together!

Best regards,
Karl

[f.albu]

Karl Ylvisaker said:

Is the SAADC generating any errors, or is it initializing and starting successfully?

The SAADC is successfully initialized and started. 

Karl Ylvisaker said:

By this, do you mean that the difference is when you enable the SoftDevice? Could you elaborate on how you included and enabled the SoftDevice?

I developed this part of the program (SAADC + FFT) based on the example of saadc and fft found in SKD17. I did the tests after modifying the project, but when I tried to join with the example of ble_app_uart_c also found in SDK17 (I just removed the part that uses the uart to receive and send the data that will be sent by ble, and this part I also tested) the buffer has stopped being filled.

I use saadc+fft to decode one mac address and use it to connect to another ble device.

Karl Ylvisaker said:

Do you mean that the PPI timer IS or ISNT timer1?
Timer0 is the one used by the SoftDevice.

Sorry, I meant I use TIMER1 for the PPI that controls the SAADC sampling

Karl Ylvisaker said:

Could you share the code where you configure and start the sampling?
Please use the "insert -> Code" option when doing so.

void timer_handler(nrf_timer_event_t event_type, void * p_context)
{
    flag_adc = true;
}


void saadc_sampling_event_init(void)
{
    ret_code_t err_code;

    err_code = nrf_drv_ppi_init();
    APP_ERROR_CHECK(err_code);

    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.bit_width = NRF_TIMER_BIT_WIDTH_32;
    err_code = nrf_drv_timer_init(&m_timer, &timer_cfg, timer_handler);
    APP_ERROR_CHECK(err_code);

    uint32_t ticks = 100; //160000 kHz
    nrf_drv_timer_extended_compare(&m_timer,
                                   NRF_TIMER_CC_CHANNEL0,
                                   ticks,
                                   NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK,
                                   true);
    nrf_drv_timer_enable(&m_timer);

    uint32_t timer_compare_event_addr = nrf_drv_timer_compare_event_address_get(&m_timer,
                                                                                NRF_TIMER_CC_CHANNEL0);
    uint32_t saadc_sample_task_addr   = nrf_drv_saadc_sample_task_get();

    /* setup ppi channel so that timer compare event is triggering sample task in SAADC */
    err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_ppi_channel_assign(m_ppi_channel,
                                          timer_compare_event_addr,
                                          saadc_sample_task_addr);
    APP_ERROR_CHECK(err_code);
}


void saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{   
    if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
    {
        ret_code_t err_code;
        nrf_gpio_pin_toggle(NRF_GPIO_PIN_MAP(1, 11));
        err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAMPLES_IN_BUFFER);
        APP_ERROR_CHECK(err_code);
        
        if(flag_buffer == 1)
        {
            flag_buffer = 0;

        }else if(flag_buffer == 0){
            flag_buffer = 1;

        }

    }

}


void saadc_init(void)
{
    ret_code_t err_code;

    //channel config
    nrf_saadc_channel_config_t channel_config;

    channel_config.resistor_p = NRF_SAADC_RESISTOR_PULLDOWN;
    channel_config.resistor_n = NRF_SAADC_RESISTOR_DISABLED;
    channel_config.gain       = NRF_SAADC_GAIN1;
    channel_config.reference  = NRF_SAADC_REFERENCE_INTERNAL;
    channel_config.acq_time   = NRF_SAADC_ACQTIME_3US;
    channel_config.mode       = NRF_SAADC_MODE_SINGLE_ENDED;
    channel_config.pin_p      = NRF_SAADC_INPUT_AIN1;
    channel_config.pin_n      = NRF_SAADC_INPUT_DISABLED;

    //saadc config
    nrf_drv_saadc_config_t saadc_config;

    saadc_config.low_power_mode = false;
    saadc_config.resolution= NRF_SAADC_RESOLUTION_12BIT;
    saadc_config.oversample= NRF_SAADC_OVERSAMPLE_16X;
    saadc_config.interrupt_priority= APP_IRQ_PRIORITY_LOW;

    //saadc init
    err_code = nrf_drv_saadc_init(&saadc_config, saadc_callback);
    APP_ERROR_CHECK(err_code);

    //channel init
    err_code = nrf_drv_saadc_channel_init(0, &channel_config);
    APP_ERROR_CHECK(err_code);

    //buffer init (duble)
    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1], SAMPLES_IN_BUFFER);
    APP_ERROR_CHECK(err_code);

    //continous mode
//    nrf_saadc_continuous_mode_enable(100); //10khz enchantilionage
//    nrf_saadc_task_trigger(NRF_SAADC_TASK_START);
//    nrf_saadc_task_trigger(NRF_SAADC_TASK_SAMPLE);
//    nrf_saadc_int_enable(NRF_SAADC_INT_END);

    saadc_sampling_event_init();

}

The idea for the future is to have several devices that all are configured as ble peripherals and when they receive an indication (boot status) it starts to behave as a central ble to connect to a specific device (through the mac address received using saadc + fft) to exchange data.

Best regards,
Fernando

[Karl Ylvisaker]

Hello Fernando,

f.albu said:

The SAADC is successfully initialized and started. 

Please elaborate how you have verified this. If it is started, I would assume that the buffer would begin filling shortly after.
How are you verifying whether the buffer is being filled or not? 
And what is your intended sampling frequency?

f.albu said:

I developed this part of the program (SAADC + FFT) based on the example of saadc and fft found in SKD17. I did the tests after modifying the project, but when I tried to join with the example of ble_app_uart_c also found in SDK17 (I just removed the part that uses the uart to receive and send the data that will be sent by ble, and this part I also tested)

Just to make sure I have understood you intentions correctly - you successfully implemented your desired SAADC + FFT functionality in the SAADC example from the SDK, before you copied this code into the ble_app_uart_c BLE central example from the SDK. You then removed the parts of the example responsible for receiving and sending UART messages, and replaced it by your SAADC outputs instead?

f.albu said:

I use saadc+fft to decode one mac address and use it to connect to another ble device.

So, you are receiving a signal on your SAADC input that is a mac address encoded using FFT, have I understood you correctly?

f.albu said:

Sorry, I meant I use TIMER1 for the PPI that controls the SAADC sampling

Thank you for clarifying.

f.albu said:

The idea for the future is to have several devices that all are configured as ble peripherals and when they receive an indication (boot status) it starts to behave as a central ble to connect to a specific device (through the mac address received using saadc + fft) to exchange data.

I see. Have you seen the experimental multirole example from the SDK?
It demonstrates functionality similar to what you describe.

Looking forward to resolving this issue together!

Best regards,
Karl

[f.albu]

Karl Ylvisaker said:

Please elaborate how you have verified this. If it is started, I would assume that the buffer would begin filling shortly after.

To verify that the SAADC was well initiated, I checked the recorders with the help of segger. As you can see in the text below.

SAADC                                          
    TASKS_START                                
        TASKS_START                            
    TASKS_SAMPLE                               
        TASKS_SAMPLE                           
    TASKS_STOP                                 
        TASKS_STOP                             
    TASKS_CALIBRATEOFFSET                      
        TASKS_CALIBRATEOFFSET                  
    EVENTS_STARTED               0x00000000    
        EVENTS_STARTED           0             
    EVENTS_END                   0x00000001    
        EVENTS_END               1             
    EVENTS_DONE                  0x00000001    
        EVENTS_DONE              1             
    EVENTS_RESULTDONE            0x00000001    
        EVENTS_RESULTDONE        1             
    EVENTS_CALIBRATEDONE         0x00000000    
        EVENTS_CALIBRATEDONE     0             
    EVENTS_STOPPED               0x00000000    
        EVENTS_STOPPED           0             
    INTEN                        0x00000002    
        STARTED                  0             
        END                      1             
        DONE                     0             
        RESULTDONE               0             
        CALIBRATEDONE            0             
        STOPPED                  0             
        CH0LIMITH                0             
        CH0LIMITL                0             
        CH1LIMITH                0             
        CH1LIMITL                0             
        CH2LIMITH                0             
        CH2LIMITL                0             
        CH3LIMITH                0             
        CH3LIMITL                0             
        CH4LIMITH                0             
        CH4LIMITL                0             
        CH5LIMITH                0             
        CH5LIMITL                0             
        CH6LIMITH                0             
        CH6LIMITL                0             
        CH7LIMITH                0             
        CH7LIMITL                0             
    INTENSET                     0x00000002    
        STARTED                  0             
        END                      1             
        DONE                     0             
        RESULTDONE               0             
        CALIBRATEDONE            0             
        STOPPED                  0             
        CH0LIMITH                0             
        CH0LIMITL                0             
        CH1LIMITH                0             
        CH1LIMITL                0             
        CH2LIMITH                0             
        CH2LIMITL                0             
        CH3LIMITH                0             
        CH3LIMITL                0             
        CH4LIMITH                0             
        CH4LIMITL                0             
        CH5LIMITH                0             
        CH5LIMITL                0             
        CH6LIMITH                0             
        CH6LIMITL                0             
        CH7LIMITH                0             
        CH7LIMITL                0             
    INTENCLR                     0x00000002    
        STARTED                  0             
        END                      1             
        DONE                     0             
        RESULTDONE               0             
        CALIBRATEDONE            0             
        STOPPED                  0             
        CH0LIMITH                0             
        CH0LIMITL                0             
        CH1LIMITH                0             
        CH1LIMITL                0             
        CH2LIMITH                0             
        CH2LIMITL                0             
        CH3LIMITH                0             
        CH3LIMITL                0             
        CH4LIMITH                0             
        CH4LIMITL                0             
        CH5LIMITH                0             
        CH5LIMITL                0             
        CH6LIMITH                0             
        CH6LIMITL                0             
        CH7LIMITH                0             
        CH7LIMITL                0             
    STATUS                       0x00000001    
        STATUS                   1             
    ENABLE                       0x00000001    
        ENABLE                   1             
    RESOLUTION                   0x00000002    
        VAL                      2             
    OVERSAMPLE                   0x00000004    
        OVERSAMPLE               4             
    SAMPLERATE                   0x00000000    
        CC                       0x000         
        MODE                     0             
    EVENTS_CH[0].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[0].LIMITL          0x00000000    
        LIMITL                   0             
    EVENTS_CH[1].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[1].LIMITL          0x00000000    
        LIMITL                   0             
    EVENTS_CH[2].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[2].LIMITL          0x00000000    
        LIMITL                   0             
    EVENTS_CH[3].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[3].LIMITL          0x00000000    
        LIMITL                   0             
    EVENTS_CH[4].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[4].LIMITL          0x00000000    
        LIMITL                   0             
    EVENTS_CH[5].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[5].LIMITL          0x00000000    
        LIMITL                   0             
    EVENTS_CH[6].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[6].LIMITL          0x00000000    
        LIMITL                   0             
    EVENTS_CH[7].LIMITH          0x00000000    
        LIMITH                   0             
    EVENTS_CH[7].LIMITL          0x00000000    
        LIMITL                   0             
    CH[0].PSELP                  0x00000002    
        PSELP                    2             
    CH[0].PSELN                  0x00000000    
        PSELN                    0             
    CH[0].CONFIG                 0x00000501    
        RESP                     1             
        RESN                     0             
        GAIN                     5             
        REFSEL                   0             
        TACQ                     0             
        MODE                     0             
        BURST                    0             
    CH[0].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    CH[1].PSELP                  0x00000000    
        PSELP                    0             
    CH[1].PSELN                  0x00000000    
        PSELN                    0             
    CH[1].CONFIG                 0x00020000    
        RESP                     0             
        RESN                     0             
        GAIN                     0             
        REFSEL                   0             
        TACQ                     2             
        MODE                     0             
        BURST                    0             
    CH[1].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    CH[2].PSELP                  0x00000000    
        PSELP                    0             
    CH[2].PSELN                  0x00000000    
        PSELN                    0             
    CH[2].CONFIG                 0x00020000    
        RESP                     0             
        RESN                     0             
        GAIN                     0             
        REFSEL                   0             
        TACQ                     2             
        MODE                     0             
        BURST                    0             
    CH[2].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    CH[3].PSELP                  0x00000000    
        PSELP                    0             
    CH[3].PSELN                  0x00000000    
        PSELN                    0             
    CH[3].CONFIG                 0x00020000    
        RESP                     0             
        RESN                     0             
        GAIN                     0             
        REFSEL                   0             
        TACQ                     2             
        MODE                     0             
        BURST                    0             
    CH[3].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    CH[4].PSELP                  0x00000000    
        PSELP                    0             
    CH[4].PSELN                  0x00000000    
        PSELN                    0             
    CH[4].CONFIG                 0x00020000    
        RESP                     0             
        RESN                     0             
        GAIN                     0             
        REFSEL                   0             
        TACQ                     2             
        MODE                     0             
        BURST                    0             
    CH[4].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    CH[5].PSELP                  0x00000000    
        PSELP                    0             
    CH[5].PSELN                  0x00000000    
        PSELN                    0             
    CH[5].CONFIG                 0x00020000    
        RESP                     0             
        RESN                     0             
        GAIN                     0             
        REFSEL                   0             
        TACQ                     2             
        MODE                     0             
        BURST                    0             
    CH[5].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    CH[6].PSELP                  0x00000000    
        PSELP                    0             
    CH[6].PSELN                  0x00000000    
        PSELN                    0             
    CH[6].CONFIG                 0x00020000    
        RESP                     0             
        RESN                     0             
        GAIN                     0             
        REFSEL                   0             
        TACQ                     2             
        MODE                     0             
        BURST                    0             
    CH[6].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    CH[7].PSELP                  0x00000000    
        PSELP                    0             
    CH[7].PSELN                  0x00000000    
        PSELN                    0             
    CH[7].CONFIG                 0x00020000    
        RESP                     0             
        RESN                     0             
        GAIN                     0             
        REFSEL                   0             
        TACQ                     2             
        MODE                     0             
        BURST                    0             
    CH[7].LIMIT                  0x7fff8000    
        LOW                      0x8000        
        HIGH                     0x7fff        
    RESULT.PTR                   0x20003c3c    
        PTR                      0x20003c3c    
    RESULT.MAXCNT                0x00000080    
        MAXCNT                   0x0080        
    RESULT.AMOUNT                0x00000080    
        AMOUNT                   0x0080        

Karl Ylvisaker said:

How are you verifying whether the buffer is being filled or not?

First I checked through the watch that my buffer variable was not being modified, after I checked that the RESULT.PTR register is not being modified either. 

Karl Ylvisaker said:

And what is your intended sampling frequency?

I need a 10kHz sampling frequency. But as I use oversampling in x16, I set it to have a sampling frequency of 160kHz.

Karl Ylvisaker said:

Just to make sure I have understood you intentions correctly - you successfully implemented your desired SAADC + FFT functionality in the SAADC example from the SDK, before you copied this code into the ble_app_uart_c BLE central example from the SDK. You then removed the parts of the example responsible for receiving and sending UART messages, and replaced it by your SAADC outputs instead?

That's right, but the message I send is the value of the power of a specific frequency, which I obtain through the treatment of the signal sampled

Karl Ylvisaker said:

So, you are receiving a signal on your SAADC input that is a mac address encoded using FFT, have I understood you correctly?

Is the MAC address modulated in frequency

Karl Ylvisaker said:

I see. Have you seen the experimental multirole example from the SDK?

Yes, I've seen it, but for now I've left defined the roles of each module (or central or peripheral)

Best regards,
Fernando

[Karl Ylvisaker]

Hello Fernando,

Thank you for elaborating, this greatly helps my understanding of your project.
I at least do not immediately see anything wrong with the setup and configuration of the SAADC that you have shared. However, I can not see that you are calling nrf_drv_ppi_channel_enable
anywhere. Could you confirm for me that this is in fact done?

f.albu said:

First I checked through the watch that my buffer variable was not being modified, after I checked that the RESULT.PTR register is not being modified either. 

Is the application functioning as expected, with the exception of the SAADC?
Are you able to verify that the device has not become stuck somewhere, as a part of the added SoftDevice code?
For example, does the SoftDevice / BLE communication with the device function as expected?

Best regards,
Karl

[f.albu]

Karl Ylvisaker said:

I can not see that you are calling nrf_drv_ppi_channel_enable
anywhere. Could you confirm for me that this is in fact done?

I do that in the main function.

I think I found a solution, I changed the SAADC priority to APP_IRQ_PRIORITY_THREAD in their initialization but I don't know if it's the best (if it will cause problems in the future with the messages sent by ble)

    saadc_config.resolution= NRF_SAADC_RESOLUTION_12BIT;
    saadc_config.oversample= NRF_SAADC_OVERSAMPLE_16X;
    saadc_config.interrupt_priority= APP_IRQ_PRIORITY_THREAD;

    //saadc init
    err_code = nrf_drv_saadc_init(&saadc_config, saadc_callback);
    APP_ERROR_CHECK(err_code);