Play Audio in nrf52 boards

[Yesha Patel]

How to Play Audio (.wav file) like human voice not the beep sound in nrf52832 boards?

[Hung Bui]

Hi Yesha, 

I would suggest to have a look at this case:  Play audio snippet via nRF51/52 

You can either use PWM or I2S to output the audio. 

For PWM, you would need to convert the sound to PCM format and use PWM to output the PCM data. It's is similar to what we did with the Thingy 52. I think it's a good example that you can follow.  

[Yesha Patel]

Hi Hung,

I used the PWM to output the audio, used this example https://sourceforge.net/projects/nrf52-pwm-audio/ and other audio code example with different sample audios also but it's not giving the original audio, I got lots of noise can you suggest what can be the issue?

Thanks,

Yesha.

[Hung Bui]

Hi, 
Could you please send your schematic and a picture of your set-up ? 

[Yesha Patel]

Hi,

I have the custom board of nrf52832 for which the speaker is already inbuilt, it works for beep sequence 

static uint16_t /*const*/ seq_values[] =
{
0x8000, 0,
0x8000, 0,
0x8000, 0,
0x8000, 0,
0x8000, 0,
0x8000, 0,
0x8000, 0,
0x8000, 0,
0x8000, 0
};


nrf_pwm_sequence_t const seq =
{
.values.p_common = seq_values,
.length = NRF_PWM_VALUES_LENGTH(seq_values),
.repeats = 0,
.end_delay = 0
};

but when I tried to use wav file hex code it's making noise

[ovrebekk]

Hi 

You have to configure the PWM according to the format of the sound file, with countertop set to 255, and ensure that the wave file is using an 8-bit unsigned format. Secondly, you need to do some processing on your audio data in order to convert the 8-bit samples from the wave file to 16-bit unsigned values for the PWM module. 

What was your problem when running the sourceforge project? 

Did you get the code to work with the included wave files, but not your own? 

Best regards
Torbjørn