NRF5340 UART completely turn off and turn on dynamically in app program

[saeed mahvis]

Hello

I am using NRF5340 as Soc in my project. In application program I have used uart0 for data transfer. At the same time the power consumption is really important for me

because the board is battery powered. So in idle times I turn off the uart0 by NRF_UARTE0->ENABLE = 0   command and turn it on again by NRF_UARTE0->ENABLE = 8

command. In this way I can reduce the current consumption from 1.5ma to 0.84ma. The problem is that when I add  CONFIG_SERIAL=n in the prj.conf file the current

reduces more and goes to 0.48ma. As far as I could understand from the dev zone studies the NRF_UARTE0->ENABLE = 0 command doesn't turn off the clock of uart0

but the command CONFIG_SERIAL=n does. Now I want to to know how can I completely turn off uart0 in my application program(not by prj.conf modification) and also

turn it on again. Thank you in advance for you support.

[Simon]

To enable/disable UART dynamically in your program you can set CONFIG_PM_DEVICE=y and use pm_device_action_run(). Check out the modem shell sample to see how to use this function.

Best regards,

Simon

[saeed mahvis]

Hi Simon

I have added CONFIG_PM_DEVICE=y in the prj.config and also added the modem shell sample code in my program.

 I only used the code for uart0. But the sdk can not recognize pm_device_action_run() function and issued

(undefined reference to `pm_device_action_run')

static void uart0_set_enable(bool enable)
{
	const struct device *uart_dev = DEVICE_DT_GET(DT_NODELABEL(uart0));

	if (!device_is_ready(uart_dev)) {
		return;
	}

	pm_device_action_run(uart_dev, enable ? PM_DEVICE_ACTION_RESUME : PM_DEVICE_ACTION_SUSPEND);
}
void disable_uarts(void)
{
	uart0_set_enable(false);
	//uart1_set_enable(false);
}

void enable_uarts(void)
{
	uart0_set_enable(true);
	//uart1_set_enable(true);
}

error.

[Simon]

Did you add #include <pm/device.h> at the top? What version of NCS are you using?

Here I added pm_device_action_run to the hello world sample in NCS v1.9.1 and it built anbd ran successfully:

hello_world_disable_uart_runtime.zip

Here I used a delay between the calls, but that may cause some issues as mentioned in this ticket:  NCS Uart Console Suspend Before Log Outpput  

Best regards,

Simon

[saeed mahvis]

Hi again

Yes I have added #include <pm/device.h> at the top. But the NCS version I am using is v1.8.0

I will install your version and try it again and inform you. Thank you for your response

[saeed mahvis]

Hi

Your hello_world_disable_uart_runtime was compiled with no errors in NCS v1.9.1 but in version

v1.8.0 it couldn't be compiled. So I will try my own program by v1.9.1 and inform you

B.S

[Simon]

saeed mahvis said:

So I will try my own program by v1.9.1 and inform you

Sounds good