How can I extend the range of the fft result graph of x-axis?

RE: How can I extend the range of the fft result graph of x-axis?

Marjeris Romero — Wed, 04 Dec 2019 13:24:15 GMT

Hi,

Sorry for the late answer. The UART module is initialized already in nrf_log_backend_uart.c, you don't need initialize the module in main.c again.

Best regards,

Marjeris

RE: How can I extend the range of the fft result graph of x-axis?

zester926 — Fri, 22 Nov 2019 10:50:04 GMT

I told you aobve.. when I enabled NRF_LOG_BACKEND_UART_ENABLED AND unenabled NRF_LOG_BACKEND_RTT_ENABLED, it occurs error.

I set the properties of UART correctly like what you said.

The error occurs here,

when check the result of APP_UART_FIFO_INIT, it occurs error

RE: How can I extend the range of the fft result graph of x-axis?

Marjeris Romero — Fri, 22 Nov 2019 09:53:26 GMT

Hi,

To use Putty you need to enable NRF_LOG_BACKEND_UART_ENABLED in sdk_config.h:

// <e> NRF_LOG_BACKEND_UART_ENABLED - nrf_log_backend_uart - Log UART backend
//==========================================================
#ifndef NRF_LOG_BACKEND_UART_ENABLED
#define NRF_LOG_BACKEND_UART_ENABLED 1
#endif

This is also enable by default in the fpu_ftt example. Use the following UART settings:

Baud rate: 115.200
8 data bits
1 stop bit
No parity
HW flow control: None

RE: How can I extend the range of the fft result graph of x-axis?

zester926 — Thu, 21 Nov 2019 03:12:10 GMT

Hi msromero!

I defined nrf_log_backend_uart_enabled and added the src code of nrf_log_backend_uart.c.

but when I run the program it occurs error at uart_init().

What would be the problem?

Best regards,

Baek

RE: How can I extend the range of the fft result graph of x-axis?

zester926 — Thu, 21 Nov 2019 02:10:54 GMT

Hi msromero!

Thank you but, is that possible checking the output of NRF_LOG_RAW_INFO() at the PuTTY?

and how should I set the sdk_config to check the output at the PuTTY?

Best regards,

Baek

RE: How can I extend the range of the fft result graph of x-axis?

Marjeris Romero — Wed, 20 Nov 2019 12:09:30 GMT

Hi Baek,

I don't mean changing the actual size of the terminal window, but changing how many characters you can fit in the window. But I am not sure how to do this in RTT Viewer. Can you try to test using PuTTY and adjusting the column option I mentioned earlier to see if this is the root of the problem?

Best regards,

Marjeris

RE: How can I extend the range of the fft result graph of x-axis?

zester926 — Tue, 19 Nov 2019 12:54:40 GMT

Hi msromero!

Thank you for your care.

Well, I'm using RTT Viewer now, and when I change the size of the window, Anything changed. :(

I took some images of several ranges.

1. 1000hz

2. 1500hz

3. 2000hz

4. 2500hz

5. 3000hz

As you can see the image, It is shifted to the left when It reaches over 2000hz.

And the graph looks symmetrical, is this why it takes up the space?

Best regards,

Baek

RE: How can I extend the range of the fft result graph of x-axis?

Marjeris Romero — Mon, 18 Nov 2019 11:55:54 GMT

Hi,

The limit of the x-axis is determined by the FFT_TEST_OUT_SAMPLES_LEN defined, which in your case will be 256, which looks correct. My guess is that the terminal window is too little and that's why the graph is being shifted to the left. Which terminal are you using to output the results? If you are using PuTTY you can modify the size of the terminal window by changing the "Columns" field under the "Window" options.

Best regards,

Marjeris