How to modify the PWM value with easydma for NRF52???

RE: How to modify the PWM value with easydma for NRF52???

Ole Bauck — Tue, 23 Aug 2016 15:17:58 GMT

then you have to set the load to waveform (see product specification for how this works):

.load_mode    = PWM_DECODER_LOAD_WaveForm

And use nrf_pwm_values_wave_form_t struct for the values.

RE: How to modify the PWM value with easydma for NRF52???

Zkernel — Tue, 23 Aug 2016 03:23:18 GMT

Thank you very much, duty than I can be changed. now ，i want change the cycle?

  typedef struct
{
    uint16_t period  ;
    nrf_pwm_values_grouped_t  P_groups; 
} nrf_pwm_running_values; 

static nrf_pwm_running_values nrf_pwm={10000,{100,100|0x8000}};


 static nrf_pwm_sequence_t const pwm0_seq =
    {
        .values.p_grouped = &nrf_pwm.P_groups,
        .length           = 2,
        .repeats          = 0,
        .end_delay        = 0
    };

This is my definition of a cycle and duty cycle of the structure, when I serial interface to modify the structure，but cycle has not changed.

static void nus_data_handler(ble_nus_t * p_nus, uint8_t * p_data, uint16_t length)
{
    for (uint32_t i = 0; i < length; i++)
    {
        while(app_uart_put(p_data[i]) != NRF_SUCCESS);
        SEGGER_RTT_printf(0,"UART DATA %02X \n\n",p_data[i]) ; 
    }
    nrf_pwm.period=20000;
    nrf_pwm.P_groups.group_0=200;
    nrf_pwm.P_groups.group_1=200|0x8000;
    nrf_drv_pwm_simple_playback(&m_pwm0, &pwm0_seq, 1,
    NRF_DRV_PWM_FLAG_LOOP);
    while(app_uart_put('\n') != NRF_SUCCESS);
}

RE: How to modify the PWM value with easydma for NRF52???

Ole Bauck — Mon, 22 Aug 2016 14:50:44 GMT

This code will setup PWM on one pin. You can update the duty cycle between 0 and m_top:

static uint16_t const m_top  = 10000;

static nrf_pwm_values_common_t m_seq_values;
static nrf_pwm_sequence_t const m_seq =
{
    .values.p_common    = &m_seq_values,
    .length              = NRF_PWM_VALUES_LENGTH(m_seq_values),
    .repeats             = 0,
    .end_delay           = 0
};

static void pwm_init(void)
{
    uint32_t err_code;
    nrf_drv_pwm_config_t const config0 =
    {
        .output_pins =
        {
            BSP_LED_0 | NRF_DRV_PWM_PIN_INVERTED, // channel 0
            NRF_DRV_PWM_PIN_NOT_USED, // channel 1
            NRF_DRV_PWM_PIN_NOT_USED, // channel 2
            NRF_DRV_PWM_PIN_NOT_USED  // channel 3
        },
        .irq_priority = APP_IRQ_PRIORITY_LOW,
        .base_clock   = NRF_PWM_CLK_1MHz,
        .count_mode   = NRF_PWM_MODE_UP,
        .top_value    = m_top,
        .load_mode    = NRF_PWM_LOAD_COMMON,
        .step_mode    = NRF_PWM_STEP_AUTO
    };
    err_code = nrf_drv_pwm_init(&m_pwm0, &config0, NULL);
    APP_ERROR_CHECK(err_code);
    m_used |= USED_PWM(0);
}

void update_pwm(int16_t duty_cycle)
{
    m_seq_values = duty_cycle;
    nrf_drv_pwm_simple_playback(&m_pwm0, &m_seq, 1, 0);
}