How do I power off the UART

RE: How do I power off the UART

Achim Kraus — Sat, 17 Dec 2022 15:49:13 GMT

> you can close this ticket.

I'm an other user, it's up to you to click "Verify Answer" ;-)

RE: How do I power off the UART

Timothy — Thu, 15 Dec 2022 14:06:47 GMT

Achim

I used the second method with CONFIG_SERIAL=y and pm_device_state_set(uart_dev,PM_DEVICE_STATE_OFF); it does disable the UARt and does not crash. The production application continues to run. Thank you very much. you can close this ticket.

RE: How do I power off the UART

Achim Kraus — Wed, 14 Dec 2022 17:27:06 GMT

Hm, not sure, maybe it was somehow mixed up:

If "CONFIG_SERIAL=n" is used, then you don't need the "power_manager" stuff.

So the part:

#if 1
/*Option 3: by chosen node*/
#define MY_SERIAL DT_CHOSEN(zephyr_console)
const struct device *uart_dev = device_get_binding(DT_LABEL(MY_SERIAL));
pm_device_state_set(uart_dev,PM_DEVICE_STATE_OFF);
#endif

must/may be switched off by "#if 0".

If "CONFIG_SERIAL=y" is used, then you may use the "power_manager" stuff. But don't call "pm_device_state_set(uart_dev,PM_DEVICE_STATE_OFF);" unconditional. I would always guard that with

if (device_is_ready(uart_dev)) {
pm_device_state_set(uart_dev,PM_DEVICE_STATE_OFF);
}

that doesn't crash, even if "uart_dev" is NULL.

RE: How do I power off the UART

Timothy — Wed, 14 Dec 2022 16:31:32 GMT

Achim

if I put this at the start of main

void main(void)
{
int err;

*******************************

I get the following repeated. I am not able to upgrade to a later version. There is a lot of customer and device driver code that would have to be ported.. so a lot of the printout is disabled but it is not running my program. it is just continually rebooting.

I: Boot source: none
I: Swap type: none
I: Bootloader chainload address offset: 0x10000
I: Starting bootloadert image slot
I: Primary image: magic=good, swap_type=0x2, copy_done=0x1, image_ok=0x1
I: Secondary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3
I: Boot source: none
I: Swap type: none
I: Bootloader chainload address offset: 0x10000
I: Starting bootloadert image slot
I: Primary image: magic=good, swap_type=0x2, copy_done=0x1, image_ok=0x1
I: Secondary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3
I: Boot source: none
I: Swap type: none

RE: How do I power off the UART

Achim Kraus — Wed, 14 Dec 2022 15:52:23 GMT

> v2.6.99-ncs1

I use NCS 2.1.2 with v3.1.99-ncs1-1. I'm not sure, what that older version offers.

> CONFIG_SERIAL=n

I guess your code access that device "unconditional".

> ../src/jfet_files/jfet_init.c: fatal error: power_manager.h: No such file or directory

I guess, that requires a newer version, e.g. NCS 2.1.2

Anyway, for a fast solution without update to NCS 2.1.2, I would recommend, that you try one of the samples, e.g. blinky with CONFIG_SERIAL=n and see, if that works. Or the nrf9160 udp sample.

If so, the try to find, where your code access the uart.

If the blinky doesn't work, then I'm not sure, if that's related to OS version.

RE: How do I power off the UART

Timothy — Wed, 14 Dec 2022 14:37:55 GMT

Achim - I tried the static method by setting CONFIG_SERIAL=n in prj.conf and I got the following repeatedly.

*** Booting Zephyr OS build v2.6.99-ncs1 ***
I: Starting bootloader
I: Primary image: magic=good, swap_type=0x2, copy_done=0x1, image_ok=0x1
I: Secondary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3
I: Boot source: none
I: Swap type: none
I: Bootloader chainload address offset: 0x10000
*** Booting Zephyr OS build v2.6.99-ncs1 ***
I: Starting bootloader
I: Primary image: magic=good, swap_type=0x2, copy_done=0x1, image_ok=0x1
I: Secondary image: magic=unset, swap_type=0x1, copy_done=0x3, image_ok=0x3
I: Boot source: none
I: Swap type: none
I: Bootloader chainload address offset: 0x10000

I tried the dynamic message and I got the following message

../src/jfet_files/jfet_init.c: fatal error: power_manager.h: No such file or directory

any idea what I am missing or doing wrong in either case?

RE: How do I power off the UART

ovrebekk — Wed, 14 Dec 2022 10:15:48 GMT

Hi Timothy

I agree with the suggestions from Achim.

For further reading this blog has a lot of good input on power management in general. It is targeted for nRF5340 designs specifically, but a lot of the information in the blog will be relevant for other devices as well.

Best regards
Torbjørn

RE: How do I power off the UART

Achim Kraus — Wed, 14 Dec 2022 08:45:52 GMT

AFAIK, there are two ways:

static:

- CONFIG_SERIAL=n

dynamic:

- CONFIG_PM_DEVICE=y

#include "power_manager.h"
static const struct device *const uart0_dev = DEVICE_DT_GET_OR_NULL(DT_CHOSEN(zephyr_console));

 if (device_is_ready(uart0_dev)) {
 ret = pm_device_action_run(uart0_dev, PM_DEVICE_ACTION_SUSPEND);}