voice output using PWM

[air]

 Hello,

I'm trying to play voice using PWM in nRF51822.

I've already experienced this using other MCU before.

So. I'm trying.

Voice source data is 8bit / 8K / mono PCM sampling data.

I call below code according to 8KHz frequency.

I write the above PCM sampling data value to below level register.

The val register value is a fixed value of 50.

At the test level, I don't execute any other code, but only this code.

And the below code is used for buzzer playback now.

I don't know what's wrong.

Could anybody let me know what's wrong or some tip?

 Thanks and happy new year.

*****************************************************************************************

// for sound level

err_code = app_pwm_uninit(&PWM_BUZZER);
// NRF_LOG_RAW_INFO("pwm-buzzer uninit error : %d\r\n", err_code);
APP_ERROR_CHECK(err_code);

app_pwm_config_t pwm1_cfg = APP_PWM_DEFAULT_CONFIG_1CH(level, BUZZER_PIN);
pwm1_cfg.pin_polarity[0] = APP_PWM_POLARITY_ACTIVE_HIGH;

err_code = app_pwm_init(&PWM_BUZZER, &pwm1_cfg, NULL); // callback_pwmBuz);
// NRF_LOG_RAW_INFO("pwm-buzzer init error : %d\r\n", err_code);
APP_ERROR_CHECK(err_code);

app_pwm_enable(&PWM_BUZZER);
// NRF_LOG_RAW_INFO("pwm-buzzer enable\r\n");

// for sound strength
while(app_pwm_channel_duty_set(&PWM_BUZZER, 0, val) == NRF_ERROR_BUSY);

*****************************************************************************************

[air]

There is something wrong.
I write 125L(125uS for 8K sampling) into the level register and PCM sampling data into the val register.

* @param [in] duty Duty cycle (0 - 100)

I wonder if the duty value can be applied to other values.
For example, 0 ~ 255 for 8bit sampling and 0 ~ 65535 for 16bit sampling.