Questions about Github example, ble_app_uart_saadc_timer_driven_scan_mode

RE: Questions about Github example, ble_app_uart_saadc_timer_driven_scan_mode

KYUBEEN — Tue, 02 Apr 2019 06:54:41 GMT

Thanks Jorgen, It works for me well !!

Have a great day

RE: Questions about Github example, ble_app_uart_saadc_timer_driven_scan_mode

Jørgen Holmefjord — Mon, 01 Apr 2019 16:19:05 GMT

You can do something like this (given that you keep the SAMPLES_IN_BUFFER at 4):

uint8_t nus_string[20];
int n = sprintf(nus_string, "%d\r\n%d\r\n%d\r\n%d\r\n", p_event->data.done.p_buffer[0], p_event->data.done.p_buffer[1], p_event->data.done.p_buffer[2], p_event->data.done.p_buffer[3]);

if(n <= 20) 
{
	bytes_to_send = n;
}
else 
{
	bytes_to_send = 20;
}
err_code = ble_nus_string_send(&m_nus, nus_string, bytes_to_send);
if (err_code != NRF_ERROR_INVALID_STATE) 
{
	APP_ERROR_CHECK(err_code);
}

If you have not connected the inputs, they are floating and you will get varying values in the full range of the SAADC resolution (configured at 10 bit - 0 to 1023 in the example).

RE: Questions about Github example, ble_app_uart_saadc_timer_driven_scan_mode

awneil — Mon, 01 Apr 2019 16:12:49 GMT

How to properly post code - not as an image!

[quote userid="76601" url="~/f/nordic-q-a/45592/questions-about-github-example-ble_app_uart_saadc_timer_driven_scan_mode/179567"]the yellow boxed line is like sending as string[/quote]

The function name is misleading - it sends raw bytes - not a "string" in the 'C' sense.

[quote userid="76601" url="~/f/nordic-q-a/45592/questions-about-github-example-ble_app_uart_saadc_timer_driven_scan_mode/179567"] I have no idea where can I use sprintf()[/quote]

That's a standard 'C' programming question - nothing specifically to do with Nordic!

sprintf() is part of the Standard 'C' library:

http://www.cplusplus.com/reference/cstdio/sprintf/

You use it to create a string in a buffer that you provide.

You could then transmit that buffer using ble_nus_string_send().

RE: Questions about Github example, ble_app_uart_saadc_timer_driven_scan_mode

KYUBEEN — Mon, 01 Apr 2019 16:00:00 GMT

Hi Jorgen,

Thank you for clear answer. Following the link you tagged, I found this, which seems to be a part of sending data via ble.

But the yellow boxed line is like sending as string and I have no idea where can I use sprintf() there.

Or you mean I should add another line above that yellow boxed line, like value = sprintf(value)?

And one more question is I want to figure out the meaning of the numbers, I can check with uart terminal. There are 4 samples at every event, but the number is very random in the range from about 10 to 1000. I didn't give any voltage inputs yet, so I think the value should be about 0. at least some constant value. Could u help me with this too?

Thank you for reply again.

Best regards,

Kyubeen

RE: Questions about Github example, ble_app_uart_saadc_timer_driven_scan_mode

Jørgen Holmefjord — Mon, 01 Apr 2019 12:48:59 GMT

Hi,

The example sends samples from the analog inputs, but the values are sent as binary numbers, and not strings. If you want to see the samples as strings, you can use sprintf() function to convert the sample values into a string/char array.

Best regards,
Jørgen