nrf52 ADC code based on nrfx 1.7.0 won't work on nrfx 2.1.0.

[shanyechungu]

Hi all,

I am developing ADC functions with Mynewt on nrf52 DK PCA10040 board.

The working example code based on SAADC driver nrfx 1.7.0 won't work on nrfx 2.1.0.

 Example in the Mynewt official website (https://mynewt.apache.org/latest/tutorials/sensors/nrf52_adc.html).

I searched online in the latest SDK (16.0), however, it seems that the nrfx is still the old one. It is not updated to nrfx 2.1.0 or nrfx 2.2.0. The APIs have changed but the documentations are not.

Here I list the code and the errors. I tried to modify the code to make it complie succsessfully, however, the ADC always returns a value of 0.

Would you please help check what was done wrong with the newer version of nrfx. And how I can make it work again? Thank you very much.

Example code works with nrfx 1.7.0:

#include <assert.h>
#include <os/os.h>
#include <string.h>

/* ADC */
#include "myadc/myadc.h"
#include "nrf.h"
#include <adc/adc.h>

/* Nordic headers */
#include <nrfx.h>
#include <nrf_saadc.h>
#include <nrfx_saadc.h>
#include <nrfx_config.h>

#define ADC_NUMBER_SAMPLES (2)
#define ADC_NUMBER_CHANNELS (1)

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_CONFIG;

struct adc_dev *adc;
uint8_t *sample_buffer1;
uint8_t *sample_buffer2;

void *
adc_init(void)
{
    nrf_saadc_channel_config_t cc = NRFX_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);
    cc.gain = NRF_SAADC_GAIN1_6;
    cc.reference = NRF_SAADC_REFERENCE_INTERNAL;
    adc = (struct adc_dev *) os_dev_open("adc0", 0, &adc_config);
    assert(adc != NULL);
    adc_chan_config(adc, 0, &cc);
    sample_buffer1 = malloc(adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));
    sample_buffer2 = malloc(adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));
    memset(sample_buffer1, 0, adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));
    memset(sample_buffer2, 0, adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));
    adc_buf_set(adc, sample_buffer1, sample_buffer2,
        adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));
    return adc;
}

int
adc_read(void *buffer, int buffer_len)
{
    int i;
    int adc_result;
    int my_result_mv = 0;
    int rc;
    for (i = 0; i < ADC_NUMBER_SAMPLES; i++) {
        rc = adc_buf_read(adc, buffer, buffer_len, i, &adc_result);
        if (rc != 0) {
            goto err;
        }
        my_result_mv = adc_result_mv(adc, 0, adc_result);
    }
    adc_buf_release(adc, buffer, buffer_len);
    return my_result_mv;
err:
    return (rc);
}



Error shown with version nrfx 2.1.0:

Error: libs/my_drivers/myadc/src/myadc.c:18:1: error: unknown type name 'nrfx_saadc_config_t'; did you mean 'nrf_saadc_config_t'?

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

^~~~~~~~~~~~~~~~~~~

nrf_saadc_config_t

In file included from libs/my_drivers/myadc/src/myadc.c:12:0:

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:132:5: error: field name not in record or union initializer

     .oversampling      = NRF_SAADC_OVERSAMPLE_DISABLED,                         \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:132:5: note: (near initialization for 'adc_config')

     .oversampling      = NRF_SAADC_OVERSAMPLE_DISABLED,                         \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:133:5: error: field name not in record or union initializer

     .burst             = NRF_SAADC_BURST_DISABLED,                              \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:133:5: note: (near initialization for 'adc_config')

     .burst             = NRF_SAADC_BURST_DISABLED,                              \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:133:26: error: excess elements in scalar initializer [-Werror]

     .burst             = NRF_SAADC_BURST_DISABLED,                              \

                          ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:133:26: note: (near initialization for 'adc_config')

     .burst             = NRF_SAADC_BURST_DISABLED,                              \

                          ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:134:5: error: field name not in record or union initializer

     .internal_timer_cc = 0,                                                     \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:134:5: note: (near initialization for 'adc_config')

     .internal_timer_cc = 0,                                                     \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:134:26: error: excess elements in scalar initializer [-Werror]

     .internal_timer_cc = 0,                                                     \

                          ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:134:26: note: (near initialization for 'adc_config')

     .internal_timer_cc = 0,                                                     \

                          ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:135:5: error: field name not in record or union initializer

     .start_on_end      = false,                                                 \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

repos/apache-mynewt-core/hw/mcu/nordic/src/ext/nrfx/drivers/include/nrfx_saadc.h:135:5: note: (near initialization for 'adc_config')

     .start_on_end      = false,                                                 \

     ^

libs/my_drivers/myadc/src/myadc.c:18:34: note: in expansion of macro 'NRFX_SAADC_DEFAULT_ADV_CONFIG'

nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

libs/my_drivers/myadc/src/myadc.c:18:34: error: excess elements in scalar initializer [-Werror]

libs/my_drivers/myadc/src/myadc.c:18:34: note: (near initialization for 'adc_config')

libs/my_drivers/myadc/src/myadc.c: In function 'adc_init':

libs/my_drivers/myadc/src/myadc.c:28:5: error: unknown type name 'nrfx_saadc_channel_config_t'; did you mean 'nrf_saadc_channel_config_t'?

     nrfx_saadc_channel_config_t cc = NRFX_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

     ^~~~~~~~~~~~~~~~~~~~~~~~~~~

     nrf_saadc_channel_config_t

libs/my_drivers/myadc/src/myadc.c:28:38: error: implicit declaration of function 'NRFX_SAADC_DEFAULT_CHANNEL_CONFIG_SE'; did you mean 'NRFX_SAADC_DEFAULT_CHANNEL_SE'? [-Werror=implicit-function-declaration]

     nrfx_saadc_channel_config_t cc = NRFX_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                                      NRFX_SAADC_DEFAULT_CHANNEL_SE

libs/my_drivers/myadc/src/myadc.c:29:7: error: request for member 'gain' in something not a structure or union

     cc.gain = NRF_SAADC_GAIN1_6;

       ^

libs/my_drivers/myadc/src/myadc.c:30:7: error: request for member 'reference' in something not a structure or union

     cc.reference = NRF_SAADC_REFERENCE_INTERNAL;

       ^

cc1: all warnings being treated as errors

Modified code without compiling error but with ADC value always 0: (changes are highlighted)

//nrfx_saadc_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

nrfx_saadc_adv_config_t adc_config = NRFX_SAADC_DEFAULT_ADV_CONFIG;

struct adc_dev *adc;

uint8_t *sample_buffer1;

uint8_t *sample_buffer2;

void *

adc_init(void)

{

//nrfx_saadc_channel_config_t cc = NRFX_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

//cc.gain = NRF_SAADC_GAIN1_6;

//cc.reference = NRF_SAADC_REFERENCE_INTERNAL;

nrfx_saadc_channel_t cc = NRFX_SAADC_DEFAULT_CHANNEL_SE(NRF_SAADC_INPUT_AIN1, 0);

adc = (struct adc_dev *) os_dev_open("adc0", 0, &adc_config);

assert(adc != NULL);

adc_chan_config(adc, 0, &cc);

sample_buffer1 = malloc(adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));

sample_buffer2 = malloc(adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));

memset(sample_buffer1, 0, adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));

memset(sample_buffer2, 0, adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));

adc_buf_set(adc, sample_buffer1, sample_buffer2,

adc_buf_size(adc, ADC_NUMBER_CHANNELS, ADC_NUMBER_SAMPLES));

return adc;

}

Any help is appreciated.

Thank you very much.

[Jørgen Holmefjord]

Hi,

As you figured, the nrfx 2.x API is not supported in the nRF5 SDK exactly because of the large changes in the SPI of the new nrfx_saadc driver. The driver have been completely rewritten to fix some issues seen with the old driver. The new driver will be backported to nrfx v1.8.x in the next release of nRF5 SDK, but the legacy driver will still be available. The example code needs to be completely rewritten to support the new driver. Unfortunately, for now, we do not have any examples available for the new driver. I would recommend you to stick with the driver from nrfx v1.8.x for now.

Best regards,
Jørgen

[shanyechungu]

Hi Jorgen,

Thank you for your response, although, this is a sort of disappointing.

May I know if there is a timeline Re: when the support document will be available?

Also, regarding Mynewt, do you suggest them to backport to 1.8.x as well? 

Thanks,

[Jørgen Holmefjord]

Hopefully, there will be some documentation/examples with the new driver in the next SDK release. For details on when that will be available, you need to contact your regional sales manager.

shanyechungu said:

Also, regarding Mynewt, do you suggest them to backport to 1.8.x as well?

Not necessarily, but I would recommend updating the sample/documentation to work with the new API. We are using nrfx 2.x.x in nRF Connect SDK, but it looks like the SAADC implementation in Zephyr is using HAL functions and not the new nrfx_saadc driver, so this does not provide any useful information about how to use the new API.