How to divert RTT logging to uart1 in Zephyr

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Mon, 24 Jan 2022 13:55:13 GMT

Hi,

If you want uart1 to be the console output, you populate the my_application/boards/nrf52840dk_nrf52840.overlay file with this:

/ {
  chosen {
    zephyr,console = &uart1;
  };
};

&uart1 {
  compatible = "nordic,nrf-uarte";
  status = "okay";
  current-speed = <115200>;
  tx-pin = <33>;
  rx-pin = <34>;
};

Then re-configure and flash your project.

Kind regards,

Håkon

RE: How to divert RTT logging to uart1 in Zephyr

ephimee — Mon, 24 Jan 2022 13:26:34 GMT

I now have:

CONFIG_UART_CONSOLE=y

And now hello world works.

How do I make it work for uart1 in my "big" project?

I tried to copy the same settings from hello world to my project, but I don't get any output.

This is my prj.conf:

CONFIG_NEWLIB_LIBC=y
CONFIG_NEWLIB_LIBC_NANO=n
CONFIG_SIZE_OPTIMIZATIONS=y

CONFIG_REBOOT=y
CONFIG_MAIN_STACK_SIZE=2048
CONFIG_HEAP_MEM_POOL_SIZE=32768
CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
CONFIG_STACK_SENTINEL=y

CONFIG_LOG=y
CONFIG_LOG_STRDUP_BUF_COUNT=32
CONFIG_LOG_PROCESS_THREAD_STACK_SIZE=4096
CONFIG_I2C_LOG_LEVEL_OFF=y

CONFIG_DEBUG=y
CONFIG_ASSERT=y
CONFIG_ASSERT_LEVEL=2
CONFIG_LOG_BACKEND_UART=y
CONFIG_LOG_BACKEND_RTT=n
CONFIG_USE_SEGGER_RTT=n

CONFIG_UART_CONSOLE=y
CONFIG_RTT_CONSOLE=n

CONFIG_I2C=y
CONFIG_WATCHDOG=y
CONFIG_NRFX_UARTE0=y
CONFIG_NRFX_UARTE1=y
CONFIG_NRFX_UARTE=y
CONFIG_UART_ASYNC_API=y
CONFIG_FLASH=y
CONFIG_NETWORKING=y
CONFIG_NET_SOCKETS=y
CONFIG_NET_SOCKETS_OFFLOAD=y

CONFIG_NET_IPV4=y
CONFIG_NET_IPV6=n

CONFIG_LWM2M=y
CONFIG_LWM2M_RD_CLIENT_SUPPORT_BOOTSTRAP=y
CONFIG_LWM2M_RD_CLIENT_ENDPOINT_NAME_MAX_LENGTH=64
CONFIG_LWM2M_ENGINE_DEFAULT_LIFETIME=900
CONFIG_LWM2M_COAP_BLOCK_SIZE=512
CONFIG_COAP_INIT_ACK_TIMEOUT_MS=6000
CONFIG_LWM2M_ENGINE_MAX_PENDING=10
CONFIG_LWM2M_ENGINE_MAX_REPLIES=10

CONFIG_LWM2M_DTLS_SUPPORT=y
CONFIG_NET_SOCKETS_SOCKOPT_TLS=y
CONFIG_NET_SOCKETS_OFFLOAD_TLS=n
CONFIG_NET_SOCKETS_TLS_MAX_CONTEXTS=4
CONFIG_NET_SOCKETS_ENABLE_DTLS=y
CONFIG_MBEDTLS=y
CONFIG_MBEDTLS_TLS_VERSION_1_2=y
CONFIG_MBEDTLS_SSL_MAX_CONTENT_LEN=1500
CONFIG_MBEDTLS_CIPHER_CCM_ENABLED=y
CONFIG_MBEDTLS_KEY_EXCHANGE_RSA_ENABLED=n
CONFIG_MBEDTLS_KEY_EXCHANGE_PSK_ENABLED=y
CONFIG_LWM2M_CONN_MON_OBJ_SUPPORT=y

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Mon, 24 Jan 2022 07:30:05 GMT

Hi,

printk uses the console backend for printing. You would want UART_CONSOLE set in this particular case, just to ensure that the pinout itself works as expected. It is very important to verify that the pinout and hardware connection is in order first, before jumping straight to the logging subsys configurations.

Kind regards,

Håkon

RE: How to divert RTT logging to uart1 in Zephyr

ephimee — Fri, 21 Jan 2022 15:31:26 GMT

[quote userid="2115" url="~/f/nordic-q-a/83517/how-to-divert-rtt-logging-to-uart1-in-zephyr/348914#348914"]Do you mean LOG_INF?[/quote]

Yes, sorry for the confusion, I meant LOG_INF.

I still don't have logging.

This is my main.c:

#include <zephyr.h>
#include <sys/printk.h>

void main(void)
{
	printk("Hello World! %s\n", CONFIG_BOARD);
}

My overlay:

/ {
  
  chosen {
    zephyr,console = &uart0;
  };
};

&uart0 {
  compatible = "nordic,nrf-uarte";
  status = "okay";
  current-speed = <115200>;
  tx-pin = <33>;
  rx-pin = <34>;
};

My CMakeLists.txt:

# SPDX-License-Identifier: Apache-2.0
  
cmake_minimum_required(VERSION 3.13.1)

# Set board folder
set(BOARD_ROOT ${CMAKE_CURRENT_LIST_DIR})

# Include the expansion board definition
set(SHIELD overlay_folder)

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
project(hello_world)

target_sources(app PRIVATE src/main.c)

My prj.conf:

# Console
CONFIG_UART_CONSOLE=n
CONFIG_RTT_CONSOLE=n

CONFIG_LOG_BACKEND_RTT=n
CONFIG_USE_SEGGER_RTT=n

# Logging
CONFIG_LOG=y
CONFIG_LOG_BACKEND_UART=y

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Fri, 21 Jan 2022 12:27:36 GMT

Hi,

My apologies for misunderstanding.

[quote user="ephimee"]because hello world uses printk and my project uses NRF_LOG?[/quote]

Do you mean LOG_INF? NRF_LOG is for nRF5 SDK.

If you get output using printk(), then the serial output is in order.

To enable LOG printing, in different modules, this is set explicitly in kconfig:

https://docs.zephyrproject.org/latest/reference/logging/index.html#logging-kconfig

here's the log subsys docs as well:

https://docs.zephyrproject.org/latest/reference/logging/index.html

First, to enable log, you need to add:

CONFIG_LOG=y

CONFIG_LOG_BACKEND_UART=y

Then you set the desired level for the module you want to log from in kconfig as well.

Kind regards,

Håkon

RE: How to divert RTT logging to uart1 in Zephyr

ephimee — Fri, 21 Jan 2022 10:09:41 GMT

I don't really understand, because hello world uses printk and my project uses NRF_LOG? That is not the same and cannot be compared.

Or maybe this is the problem that NRF_LOG cannot write to uart1?

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Thu, 20 Jan 2022 12:35:37 GMT

Hi,

If you add this overlay to the hello_world example, for testing purposes, do you get any output on uart1 then?

Kind regards,

Håkon

RE: How to divert RTT logging to uart1 in Zephyr

ephimee — Wed, 19 Jan 2022 08:20:41 GMT

Because I'm pretty new to Zephyr, I thought of a way to verify the uart1 connection.

In order to do this, I used an old project not based on Zephyr. It is based on the app_uart example from the SDK 16 library.
The project uses a BG96 modem, so what I did is change the pins of the BG96 to the uart1. Now on the USB FTDI I can see the AT commands coming in (firmware tries to communicate with BG96), thus verifying that the hardware is connected correctly and that the NRF is able to communicate over it.

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Wed, 19 Jan 2022 07:50:12 GMT

Hi,

Could you scope the TXD pin (P1.01) and see if anything outputs on this pin?

Note that this pin is not connected to the USB-UART bridge on the debugger side, so you have to manually connect your own USB-UART adapter to these two pins that you defined.

Kind regards,

Håkon

RE: How to divert RTT logging to uart1 in Zephyr

ephimee — Tue, 18 Jan 2022 20:19:36 GMT

I have the following changes in prj.conf:

CONFIG_LOG_BACKEND_UART=y
CONFIG_LOG_BACKEND_RTT=n
CONFIG_USE_SEGGER_RTT=n
CONFIG_NRFX_UARTE1=y
CONFIG_NRFX_UARTE=y

Now I don't get any logging in terminal, but also no logging on uart1.

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Mon, 17 Jan 2022 13:45:09 GMT

Hi,

[quote user="ephimee"]In the terminal window of Segger I still see all the logging.[/quote]

This is because you still have RTT enabled.

I added the same overlay to hello_world (no RTT enabled), and it prints on the tx-pin (P1.01) at my end:

Kind regards,

Håkon

RE: How to divert RTT logging to uart1 in Zephyr

ephimee — Mon, 17 Jan 2022 10:52:19 GMT

I've added this to the existing overlay:

/ {

  chosen {
    zephyr,console = &uart1;
  };
};

&uart1 {
  compatible = "nordic,nrf-uarte";
  status = "okay";
  current-speed = <115200>;
  tx-pin = <33>;
  rx-pin = <34>;
};

I added this to prj.conf:

CONFIG_LOG_BACKEND_UART=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_NRFX_UARTE1=y
CONFIG_NRFX_UARTE=y

But I still don't get anything on uart1. Am I missing something?

In the terminal window of Segger I still see all the logging.

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Mon, 17 Jan 2022 08:54:51 GMT

Hi,

[quote user="ephimee"]In the overlay file the use of &gpio1 is not allowed, but it is allowed in the dts?[/quote]

The "tx-pin" and "rx-pin" members of the uartX device reflects how the hardware peripheral requires you to specify a GPIO, as shown here:

https://infocenter.nordicsemi.com/topic/ps_nrf52840/uarte.html?cp=4_0_0_5_33_8_23#register.PSEL.TXD

The "B" field here specifies the port for bus peripherals such as UARTE.

P1.01 will then translate to "33" decimal in this register.

Kind regards,

Håkon

RE: How to divert RTT logging to uart1 in Zephyr

ephimee — Mon, 17 Jan 2022 08:45:55 GMT

In the overlay file the use of &gpio1 is not allowed, but it is allowed in the dts?

Can you explain this?

In the overlay:

&uart1 {
  compatible = "nordic,nrf-uarte";
  status = "okay";
  current-speed = <115200>;
  tx-pin = <&gpio1 1 0>;
  rx-pin = <&gpio1 2 0>;
};

In the dts:

&uart0 {
  compatible = "nordic,nrf-uarte";
  status = "okay";
  current-speed = <115200>;
  tx-pin = <44>;
  rx-pin = <30>;

  bg96 {
    compatible = "quectel,bg96";
    label = "BG96";

    reset-gpios = <&gpio1 14 0>;
    power-key-gpios = <&gpio1 15 0>;
    ring-indicator-gpios = <&gpio0 29 0>;
    dtr-gpios = <&gpio1 11 0>;
    enable-gpios = <&gpio0 27 0>;
  };
};

RE: How to divert RTT logging to uart1 in Zephyr

Håkon Alseth — Tue, 11 Jan 2022 08:04:00 GMT

Hi,

To change the console from uart0 to uart1, you can define a DT overlay file that redefines uart,console:

https://github.com/nrfconnect/sdk-zephyr/blob/main/boards/arm/nrf52840dk_nrf52840/nrf52840dk_nrf52840.dts#L15

Ie. similar to this:

/ {
	chosen {
		zephyr,console = &uart1;
	};
};


&uart1 {
    status = "okay";
    ...rest of configuration
};

Another way to switch the logging interface from uart0 to uart1 is simply to change the pin out on each of the &uart0 and &uart1 instances in device tree.

[quote user=""]I also noticed CONFIG_NRFX_UARTE0, but CONFIG_NRFX_UARTE1 does not exist? Maybe only uart0 is supported?
Do I have to reconfigure uart1 for the modem?[/quote]

It should exist: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.8.0/kconfig/CONFIG_NRFX_UARTE1.html

*edit*

To answer your main question, how to set RTT or UART backend, please see these symbols for the logging backend:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.8.0/kconfig/CONFIG_LOG_BACKEND_UART.html

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.8.0/kconfig/CONFIG_LOG_BACKEND_RTT.html

Kind regards,

Håkon