PWM

[venkatesha kj]

how to set the duty cycle of a pwm? how to set the pwm frequency?  what is that nrf_pwm_values_common_t in the pwm ?

[venkatesha kj]

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

why only 6 values what actually it represents? what actually seq_values represents? if i set the sequence value > top_value in pwm configuration waht will happen?

if i use common mode then is it sequence value range is 0-100?

[venkatesha kj]

static void demo3(void)
{
NRF_LOG_INFO("Demo 3");

/*
* This demo uses only one channel, which is reflected on LED 1.
* The LED blinks three times (200 ms on, 200 ms off), then it stays off
* for one second.
* This scheme is performed three times before the peripheral is stopped.
*/

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_LOWEST,
.base_clock = NRF_PWM_CLK_125kHz,
.count_mode = NRF_PWM_MODE_UP,
.top_value = 25000,
.load_mode = NRF_PWM_LOAD_COMMON,
.step_mode = NRF_PWM_STEP_AUTO
};
APP_ERROR_CHECK(nrf_drv_pwm_init(&m_pwm0, &config0, NULL));
m_used |= USED_PWM(0);

// This array cannot be allocated on stack (hence "static") and it must
// be in RAM (hence no "const", though its content is not changed).
static uint16_t /*const*/ seq_values[] =
{
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 = 4
};

(void)nrf_drv_pwm_simple_playback(&m_pwm0, &seq, 3, NRF_DRV_PWM_FLAG_STOP);
}

why in common mode sequence_value is 0x8000,0,0x8000,0,0x8000,0?

[venkatesha kj]

thats fine but i need to know how to set the duty cycle and frequency in the pwm driver ?