SAADC example's saadc_callback has a buffer "p_event->data.done.p_buffer" in a for loop, is not printing full buffer size data.

[Gops]

Hi.

I am using nRF52840 dongle and running saadc example on it.

To print the ADC data buffer "p_event->data.done.p_buffer" in PC, I am using USB_CDC. The size of SAMPLES_IN_BUFFER is 5.

In the "saadc_sampling_event_init()", 400 is the parameter value passed in the nrf_drv_timer_ms_to_ticks() function.

However, I am only getting one data in the for loop from the saadc_callback. Actually I should get 5 data.

Any reason why this happens?

Thank you.

[Marjeris Romero]

Hi,

How are you printing the buffer? You will either need to print each element in p_event->data.done.p_buffer:

printf("%d", p_event->data.done.p_buffer[0]);
printf("%d", p_event->data.done.p_buffer[1]);
printf("%d", p_event->data.done.p_buffer[2]);
etc,

Or you can take in the size of the pointer as an argument to know how much you need to print, for example using NRF_LOG_HEXDUMP_INFO.

Best regards,

Marjeris

[Gops]

Hi Marjeris.

Sorry for so much late.

I am filling up two buffers of 5 capacity each. I am printing as below pic, inside the call back. And I get the output as in the next pic.

The USBPrint function internally fills up a buffer containing the parameter information and does a "app_usbd_cdc_acm_write".

So, the for loop is not running correctly I guess. Or may be I am wrong and something else is there. Only two indexes are printing out of 5.

I did the way you have shared. Printed each values of the buffer individually. Still its the same output is coming on teraterm.

But I tried printing the buffer outside the call back. And all data are printed.

I have not changed the value 400 in "nrf_drv_timer_ms_to_ticks".

This number(400) is the sampling rate of the ADC. Right?

Thank you.

[Gops]

Any update Marjeris??

[Marjeris Romero]

Hi,

I am sorry for not getting back to you on this. Could you attach your whole project here so I can run and verify the issue myself?

It could be for instance that SAMPLES_IN_BUFFER is defined incorrectly, but it's difficult to point to the reason why the buffer is filling up without taking a look at the whole project.

Best regards,

Marjeris