HW PWM disturbance

RE: HW PWM disturbance

Sigurd — Thu, 23 May 2024 11:54:00 GMT

Hi!

[quote user="JonasS"]Is it possible, when we need to drive the PWM controlling the buzzer, lock it so that it not using the HFINT. And then when we not using the PWM anymore switch back letting the system switch again between the clocks?[/quote]

Yeah, absolutely.

Use
err = onoff_cancel_or_release(clk_mgr, &clk_cli);

when the PWM is not being used.

RE: HW PWM disturbance

JonasS — Thu, 23 May 2024 11:18:57 GMT

Ok, that was quite big difference.

Our product is dependent on the power consumption so I have another questions.

Is it possible, when we need to drive the PWM controlling the buzzer, lock it so that it not using the HFINT. And then when we not using the PWM anymore switch back letting the system switch again between the clocks?

Best regards Jonas

RE: HW PWM disturbance

Sigurd — Thu, 23 May 2024 09:04:53 GMT

[quote user="JonasS"]Thanks for the answer. Tried the solution and it became much better :)[/quote]

Great to hear!

[quote user="JonasS"]Could this have any impact on the power consumption? [/quote]

Yes, from the PS we have that the Run current for HFINT is 60uA, while the run current for HFXO is 250uA.

RE: HW PWM disturbance

JonasS — Thu, 23 May 2024 07:38:24 GMT

Hi!

Thanks for the answer. Tried the solution and it became much better :)

Could this have any impact on the power consumption?

BR Jonas

RE: HW PWM disturbance

Sigurd — Wed, 22 May 2024 15:39:42 GMT

Hi!

The Bluetooth stack will request the HFXO when it uses the RADIO, so you might see some small jitter when HFCLK changes between HFINT and HFXO.

You can call this function below to request HFXO to be used all the time, and see if you see any changes:

int clocks_start(void)
{
	int err;
	int res;
	struct onoff_manager *clk_mgr;
	struct onoff_client clk_cli;

	clk_mgr = z_nrf_clock_control_get_onoff(CLOCK_CONTROL_NRF_SUBSYS_HF);
	if (!clk_mgr) {
		LOG_ERR("Unable to get the Clock manager");
		return -ENXIO;
	}

	sys_notify_init_spinwait(&clk_cli.notify);

	err = onoff_request(clk_mgr, &clk_cli);
	if (err < 0) {
		LOG_ERR("Clock request failed: %d", err);
		return err;
	}

	do {
		err = sys_notify_fetch_result(&clk_cli.notify, &res);
		if (!err && res) {
			LOG_ERR("Clock could not be started: %d", res);
			return res;
		}
	} while (err);

	LOG_DBG("HF clock started");
	return 0;
}