in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

Edvin — Wed, 02 Aug 2023 07:07:39 GMT

Ah, I loaded this ticket the day before I got to write an answer, so I didn't see that you already figured it out. Glad to see that it worked out!

Best regards,
Edvin

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Tue, 01 Aug 2023 21:39:31 GMT

i used 1 <<15 to invert the pins and so now it is working like i expect.

you can just close the ticket

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

Edvin — Tue, 01 Aug 2023 08:36:43 GMT

Hello,

We are trying to balance the workloads after summer vacation, so Karl asked if I could take a look at this.

I know you have sent a lot of the FW, but is it possible to zip the application folder that you are using, and upload it here so that I can easily replicate the behavior you are seeing myself?

Also, what NCS version are you currently running?

Best regards,

Edvin

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Mon, 31 Jul 2023 17:23:15 GMT

i just changed my code to set bit 15 to invert the output and now things work like i expect.

nrf_pwm_values_individual_t static seq_blue_values[] = {
    0   | 1 <<15,
    0   | 1 <<15,
    990 | 1 <<15,
    0   | 1 <<15
    };

the top value is 1000.

maybe the inversion is in my circuit to the leds.

anyway its working now so you can close this ticket.

thanks

phil

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Sat, 22 Jul 2023 04:14:16 GMT

yes i set them to the top value so the output pin is zero. i am running an RGB led and when I want red only i want a PWM on the first pin and 0 on the next two pins. so i set the first channel to the pwm i want and the other two channels to the counter top value to get them to output a 0.

// Declare variables holding PWM sequence values. In this example only one channel is used

//nrf_pwm_values_individual_t static seq_red_values[] = {500, 0, 0, 0};

nrf_pwm_values_individual_t static seq_red_values[] = {500, 1000, 1000, 0};

nrf_pwm_sequence_t const seq_red =

{

.values.p_individual = seq_red_values,

.length = NRF_PWM_VALUES_LENGTH(seq_red_values),

.repeats = 0,

.end_delay = 0

};

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

Karl Ylvisaker — Fri, 21 Jul 2023 14:10:40 GMT

Hello again, Phil

[quote user="weightwatcherphil"]

nrf_pwm_values_individual_t static seq_off_values[] = {0, 0, 0, 0};

nrf_pwm_values_individual_t static seq_off_values[] = {1000, 1000, 1000, 0};

[/quote]

It seems to me that you are setting the values for the sequence equal to the configured top_value, is this intentional?

Best regards,
Karl

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Wed, 19 Jul 2023 14:13:03 GMT

to be really clear i have

nrfx_pwm_config_t const config1 =

{

.output_pins =

{

46 , // P1.14 channel 0 red

44 , // P1.12 channel 1 blue

47 , // P1.15 channel 2 green

NRFX_PWM_PIN_NOT_USED // channel 3

.irq_priority = NRFX_PWM_DEFAULT_CONFIG_IRQ_PRIORITY,

.base_clock = NRF_PWM_CLK_500kHz,

.count_mode = NRF_PWM_MODE_UP,

.top_value = 1000,

.load_mode = NRF_PWM_LOAD_INDIVIDUAL,

.step_mode = NRF_PWM_STEP_AUTO

//.skip_gpio_cfg = true,

//.skip_psel_cfg =false

};

nrf_pwm_values_individual_t static seq_off_values[] = {0, 0, 0, 0};

nrf_pwm_values_individual_t static seq_off_values[] = {1000, 1000, 1000, 0};

nrf_pwm_sequence_t const seq_off =

{

.values.p_individual = seq_off_values,

.length = NRF_PWM_VALUES_LENGTH(seq_purple_values),

.repeats = 0,

.end_delay = 0

};

nrfx_pwm_simple_playback(&m_pwm1, &seq_off, 1, NRFX_PWM_FLAG_LOOP);

and the output on my pins P1.14 P1,15 and P1.12 is a 1.

I expected all pins to have a 0 on the output.

thanks

phil

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Wed, 19 Jul 2023 13:24:15 GMT

when the duty cycle is 0 what value appears on the output pin ?

I thought it would be 0 but it looks like it is a '1'

i set countertop to 1000 and when the duty cycle is 1000 i get a 0 on the output.

is that correct ? I do not have bit 15 set so the output is not inverted.

thanks

phi

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

Karl Ylvisaker — Wed, 19 Jul 2023 08:24:48 GMT

[quote user="weightwatcherphil"]thanks we can close this ticket.[/quote]

No problem at all :)

[quote user="weightwatcherphil"]when the pwm is running and the duty cycle is zero does the "duty cycle" control the pwm output or does the GPIO PIN configuration control the PWM output ?[/quote]

I am not sure that I fully understand your question: When the PWM peripheral is enabled and running it will be in control of the GPIO it is configured to output to, regardless of the configured duty cycle (so also in the case that the duty cycle is 0).

Best regards,
Karl

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Tue, 18 Jul 2023 14:47:46 GMT

when the pwm is running and the duty cycle is zero does the "duty cycle" control the pwm output or does the GPIO PIN configuration control the PWM output ?

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Tue, 18 Jul 2023 14:43:43 GMT

thanks we can close this ticket.

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

Karl Ylvisaker — Tue, 18 Jul 2023 14:22:18 GMT

Hello,

I am glad to read that you now have got it working as desired! :)
For future reference the reason for the unexpected behavior here was likely the configured polarity of the PWM.

Best regards,
Karl

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Mon, 17 Jul 2023 20:35:22 GMT

i was able to get P1.14 and P1.12 to be zero by programming the duty cycle 1o 1000 instead of 0000.

so when duty cycle is 0 I get a 1 on the output and when duty cycle matches counter top (in this case 1000) i get a 0 on the output.

RE: in the nrf5340 what value appears on the hardware PWM output pin when the duty cycle is set to zero?

weightwatcherphil — Mon, 17 Jul 2023 06:20:57 GMT

when I run my program I see the proper PWM 50% duty cycle on pin 14 for the red LED. however P1.15 and P1.12 are both high and I need them to be zero.