static void init_direct_pwm(void)
{
// Get the base PWM instance (PWM20 for pwm_led0)
pwm_hw = NRF_PWM20;
// Configure PWM pins for direct access - use an array for pins
uint32_t pin_array[NRF_PWM_CHANNEL_COUNT] = {
NRF_GPIO_PIN_MAP(0, 3), // P0.03 from overlay for first channel
NRF_PWM_PIN_NOT_CONNECTED, // Unused channels
NRF_PWM_PIN_NOT_CONNECTED,
NRF_PWM_PIN_NOT_CONNECTED
};
// Set up pins properly with array
nrf_pwm_pins_set(pwm_hw, pin_array);
// With 16MHz clock, each tick is 62.5ns (1/16MHz)
// For a period of 5000ns (5μs), we need 80 ticks
// Formula: period_ticks = desired_ns / 62.5
uint32_t period_ns = 5000; // 10μs expressed in ns
period_ticks = period_ns / 62.5; // Convert ns to PWM ticks (160 ticks)
// Configure PWM parameters - 16MHz clock, counting up mode, period in ticks
nrf_pwm_configure(pwm_hw,
NRF_PWM_CLK_16MHz, // Use fastest clock (16MHz)
NRF_PWM_MODE_UP, // Count up mode
period_ticks); // Period in ticks (calculated from ns)
// Set up sequence for continuous PWM output
static nrf_pwm_sequence_t seq = {
.values.p_common = pwm_seq_values,
.length = 1,
.repeats = 0,
.end_delay = 0
};
// Configure PWM decoder for simple mode
nrf_pwm_decoder_set(pwm_hw,
NRF_PWM_LOAD_COMMON,
NRF_PWM_STEP_AUTO);
// Set up the sequence
nrf_pwm_sequence_set(pwm_hw, 0, &seq);
// Configure for infinite looping
nrf_pwm_loop_set(pwm_hw, 0xFFFF); // Loop indefinitely
// Enable PWM peripheral
nrf_pwm_enable(pwm_hw);
// Start PWM generation
nrf_pwm_task_trigger(pwm_hw, NRF_PWM_TASK_SEQSTART0);
pwm_seq_values[0] = period_ticks / 2;
nrf_pwm_task_trigger(pwm_hw, NRF_PWM_TASK_SEQSTART0);
LOG_INF("PWM Test: Set initial 50%% duty cycle (%u)", pwm_seq_values[0]);
LOG_INF("Direct PWM hardware access initialized");
}
/looping pwm code
/* Calculate PWM duty cycle */
uint16_t pwm_value = (uint16_t)(((uint64_t)period_ticks * value) / 16383U);
/* Direct hardware update */
pwm_seq_values[0] = pwm_value;
nrf_pwm_task_trigger(pwm_hw, NRF_PWM_TASK_SEQSTART0);
Hi
I am trying to port some PWM code from the NRF54L15 it uses HAL access because i have found it has faster writes which are useful for my application (testing latency and reproducing a signal) but it is building but i am not getting any outputs on the oscilloscope connected to the port 0, 03 pin. I have atteched the init code. It worked when i was using the nrf52840.
