Setting up console over SWD interface

Question

Hello,

I am trying to compile a basic Hello World application for a custom PCB with a nRF52832 microcontroller. I am using VS Code and the nRF Connect SDK. I have completed the nRF Connect SDK Fundamentals course and received the certificate, and now I am trying to apply those lessons to my custom hardware.

My goal is to compile a Hello World example and see the message printed on the VS Code console. My custom hardware does not have a UART connection broken out. I am programming my custom hardware over SWD via a nRF52-DK PCA10040 board. I would like to receive logging messages over SWD as well.

When I connect a TagConnect cable to the P19 Debug Out connector and mate it with my custom board, I can see the Connected Devices tab update from NRF52832_xxAA_REV2 to NRF52832_xxAB_REV2, so I am fairly sure that I am programming my custom board and not the DK itself.

Initially, I tried a simple printk statement, which builds and runs, but no messages are received in the terminal. After some digging in the Nordic forums, I realized that I want to use the SWD interface for console output, instead of a UART. So, I enabled logging as explained in the Fundamentals course Lesson 4 Exercise 2. I also tried changing my prj.conf to disable the UART console and enable the RTT_CONSOLE instead.

This builds and flashes without issue, but I am still not getting any of my debug messages.

How can I properly set up the SWD interface for Hello world, printk, and logging messages on a custom PCB?

main.c

/*
 * Copyright (c) 2012-2014 Wind River Systems, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/kernel.h>
#include <zephyr/logging/log.h>


LOG_MODULE_REGISTER(NixieLogs,LOG_LEVEL_DBG);

int main(void)
{
	while(true){
		printk("Hello World! %s\n", CONFIG_BOARD);
		LOG_INF("nRF Connect SDK Fundamentals");
		LOG_DBG("A log message in debug level");
		LOG_WRN("A log message in warning level!");
		LOG_ERR("A log message in Error level!");
	}
	return 0;
}

prj.conf

# nothing here

CONFIG_LOG=y

CONFIG_USE_SEGGER_RTT=y
CONFIG_RTT_CONSOLE=y
CONFIG_UART_CONSOLE=n

CMakeLists.txt

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)
list(APPEND BOARD_ROOT ${CMAKE_CURRENT_SOURCE_DIR})

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

target_sources(app PRIVATE src/main.c)

Custom PCB board defconfig

# SPDX-License-Identifier: Apache-2.0

CONFIG_SOC_SERIES_NRF52X=y
CONFIG_SOC_NRF52832_QFAA=y
CONFIG_BOARD_NIXIE_CLOCK_BOARD=y

# Enable MPU
CONFIG_ARM_MPU=y

# Enable hardware stack protection
CONFIG_HW_STACK_PROTECTION=y

# Enable RTT
CONFIG_USE_SEGGER_RTT=y

# enable GPIO
CONFIG_GPIO=y

# enable uart driver
CONFIG_SERIAL=y

# enable console
CONFIG_CONSOLE=y
CONFIG_UART_CONSOLE=y

# additional board options
CONFIG_GPIO_AS_PINRESET=y

CONFIG_PINCTRL=y

Custom board DTS file

/*
 * Copyright (c) 2017 Shawn Nock <[email protected]>
 * Copyright (c) 2017 Linaro Limited
 *
 * SPDX-License-Identifier: Apache-2.0
 */

/dts-v1/;
#include <nordic/nrf52832_qfaa.dtsi>
#include "nixie_clock_board-pinctrl.dtsi"

/ {
	model = "Chris Fernandez Nixie Clock Board";
	compatible = "chrisfernandez,nixie_clock_board";

	chosen {
		zephyr,console = &uart0;
		zephyr,shell-uart = &uart0;
		zephyr,uart-mcumgr = &uart0;
		zephyr,bt-mon-uart = &uart0;
		zephyr,bt-c2h-uart = &uart0;
		zephyr,sram = &sram0;
		zephyr,flash = &flash0;
		zephyr,code-partition = &slot0_partition;
	};

	leds {
		compatible = "gpio-leds";
		led0: led_0 {
			gpios = <&gpio0 17 GPIO_ACTIVE_LOW>;
			label = "Green LED 0";
		};
		led1: led_1 {
			gpios = <&gpio0 18 GPIO_ACTIVE_LOW>;
			label = "Green LED 1";
		};
		led2: led_2 {
			gpios = <&gpio0 19 GPIO_ACTIVE_LOW>;
			label = "Green LED 2";
		};
		led3: led_3 {
			gpios = <&gpio0 20 GPIO_ACTIVE_LOW>;
			label = "Green LED 3";
		};
	};

	pwmleds {
		compatible = "pwm-leds";
		pwm_led0: pwm_led_0 {
			pwms = <&pwm0 0 PWM_MSEC(20) PWM_POLARITY_INVERTED>;
		};
	};

	buttons {
		compatible = "gpio-keys";
		button0: button_0 {
			gpios = <&gpio0 13 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
			label = "Push button switch 0";
		};
		button1: button_1 {
			gpios = <&gpio0 14 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
			label = "Push button switch 1";
		};
		button2: button_2 {
			gpios = <&gpio0 15 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
			label = "Push button switch 2";
		};
		button3: button_3 {
			gpios = <&gpio0 16 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
			label = "Push button switch 3";
		};
	};

	arduino_header: connector {
		compatible = "arduino-header-r3";
		#gpio-cells = <2>;
		gpio-map-mask = <0xffffffff 0xffffffc0>;
		gpio-map-pass-thru = <0 0x3f>;
		gpio-map = <0 0 &gpio0 3 0>,	/* A0 */
			   <1 0 &gpio0 4 0>,	/* A1 */
			   <2 0 &gpio0 28 0>,	/* A2 */
			   <3 0 &gpio0 29 0>,	/* A3 */
			   <4 0 &gpio0 30 0>,	/* A4 */
			   <5 0 &gpio0 31 0>,	/* A5 */
			   <6 0 &gpio0 11 0>,	/* D0 */
			   <7 0 &gpio0 12 0>,	/* D1 */
			   <8 0 &gpio0 13 0>,	/* D2 */
			   <9 0 &gpio0 14 0>,	/* D3 */
			   <10 0 &gpio0 15 0>,	/* D4 */
			   <11 0 &gpio0 16 0>,	/* D5 */
			   <12 0 &gpio0 17 0>,	/* D6 */
			   <13 0 &gpio0 18 0>,	/* D7 */
			   <14 0 &gpio0 19 0>,	/* D8 */
			   <15 0 &gpio0 20 0>,	/* D9 */
			   <16 0 &gpio0 22 0>,	/* D10 */
			   <17 0 &gpio0 23 0>,	/* D11 */
			   <18 0 &gpio0 24 0>,	/* D12 */
			   <19 0 &gpio0 25 0>,	/* D13 */
			   <20 0 &gpio0 26 0>,	/* D14 */
			   <21 0 &gpio0 27 0>;	/* D15 */
	};

	arduino_adc: analog-connector {
		compatible = "arduino,uno-adc";
		#io-channel-cells = <1>;
		io-channel-map = <0 &adc 1>,	/* A0 = P0.3 = AIN1 */
				 <1 &adc 2>,	/* A1 = P0.4 = AIN2 */
				 <2 &adc 4>,	/* A2 = P0.28 = AIN4 */
				 <3 &adc 5>,	/* A3 = P0.29 = AIN5 */
				 <4 &adc 6>,	/* A4 = P0.30 = AIN6 */
				 <5 &adc 7>;	/* A5 = P0.31 = AIN7 */
	};

	/* These aliases are provided for compatibility with samples */
	aliases {
		led0 = &led0;
		led1 = &led1;
		led2 = &led2;
		led3 = &led3;
		pwm-led0 = &pwm_led0;
		sw0 = &button0;
		sw1 = &button1;
		sw2 = &button2;
		sw3 = &button3;
		bootloader-led0 = &led0;
		mcuboot-button0 = &button0;
		mcuboot-led0 = &led0;
		watchdog0 = &wdt0;
	};
};

&adc {
	status = "okay";
};

&gpiote {
	status = "okay";
};

&gpio0 {
	status = "okay";
};

arduino_serial: &uart0 {
	status = "okay";
	compatible = "nordic,nrf-uarte";
	current-speed = <115200>;
	pinctrl-0 = <&uart0_default>;
	pinctrl-1 = <&uart0_sleep>;
	pinctrl-names = "default", "sleep";
};

arduino_i2c: &i2c0 {
	compatible = "nordic,nrf-twi";
	status = "okay";
	pinctrl-0 = <&i2c0_default>;
	pinctrl-1 = <&i2c0_sleep>;
	pinctrl-names = "default", "sleep";
};

&i2c1 {
	compatible = "nordic,nrf-twi";
	/* Cannot be used together with spi1. */
	/* status = "okay"; */
	pinctrl-0 = <&i2c1_default>;
	pinctrl-1 = <&i2c1_sleep>;
	pinctrl-names = "default", "sleep";
};

&pwm0 {
	status = "okay";
	pinctrl-0 = <&pwm0_default>;
	pinctrl-1 = <&pwm0_sleep>;
	pinctrl-names = "default", "sleep";
};

&spi0 {
	compatible = "nordic,nrf-spi";
	/* Cannot be used together with i2c0. */
	/* status = "okay"; */
	pinctrl-0 = <&spi0_default>;
	pinctrl-1 = <&spi0_sleep>;
	pinctrl-names = "default", "sleep";
};

&spi1 {
	compatible = "nordic,nrf-spi";
	status = "okay";
	pinctrl-0 = <&spi1_default>;
	pinctrl-1 = <&spi1_sleep>;
	pinctrl-names = "default", "sleep";
};

arduino_spi: &spi2 {
	compatible = "nordic,nrf-spi";
	status = "okay";
	cs-gpios = <&arduino_header 16 GPIO_ACTIVE_LOW>; /* D10 */
	pinctrl-0 = <&spi2_default>;
	pinctrl-1 = <&spi2_sleep>;
	pinctrl-names = "default", "sleep";
};

&flash0 {

	partitions {
		compatible = "fixed-partitions";
		#address-cells = <1>;
		#size-cells = <1>;

		boot_partition: partition@0 {
			label = "mcuboot";
			reg = <0x00000000 0xc000>;
		};
		slot0_partition: partition@c000 {
			label = "image-0";
			reg = <0x0000C000 0x37000>;
		};
		slot1_partition: partition@43000 {
			label = "image-1";
			reg = <0x00043000 0x37000>;
		};
		storage_partition: partition@7a000 {
			label = "storage";
			reg = <0x0007a000 0x00006000>;
		};
	};
};

Custom PCB board.cmake

# SPDX-License-Identifier: Apache-2.0

board_runner_args(jlink "--device=nRF52832_xxAA" "--speed=4000")
board_runner_args(pyocd "--target=nrf52832" "--frequency=4000000")
set(OPENOCD_NRF5_SUBFAMILY "nrf52")
include(${ZEPHYR_BASE}/boards/common/nrfjprog.board.cmake)
include(${ZEPHYR_BASE}/boards/common/nrfutil.board.cmake)
include(${ZEPHYR_BASE}/boards/common/jlink.board.cmake)
include(${ZEPHYR_BASE}/boards/common/pyocd.board.cmake)
include(${ZEPHYR_BASE}/boards/common/openocd-nrf5.board.cmake)

cfernandezruns · Accepted Answer

I was able to get printk messages and log messages from my custom board. I am going to write out the changes I made in the hopes that this helps someone in the future.

In the defconfig file for my custom board:

CONFIG_UART_CONSOLE=n

In my application's prj.conf file:

CONFIG_LOG=y

CONFIG_LOG_PRINTK=y

CONFIG_USE_SEGGER_RTT=y

CONFIG_RTT_CONSOLE=y

CONFIG_UART_CONSOLE=n

main.c

#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/logging/log.h>


LOG_MODULE_REGISTER(NixieLogs,LOG_LEVEL_DBG);


#define SLEEP_TIME_MS		1000


int main(void)
{
	printk("Hello World! %s\n", CONFIG_BOARD);
	LOG_INF("nixie log info");
	LOG_DBG("nixie log debug");
	LOG_WRN("nixie log warning");
	LOG_ERR("nixie log error");

	while (1) {
        k_msleep(SLEEP_TIME_MS); 
	}
	return 0;
}

project.code-workspace: a new 'settings' list showed up, listing nrf-connect.applications.

{
    "folders": [
        {
            "path": "hello_world"
        }
    ],
    "settings": {
        "nrf-connect.applications": [],
    }
}

I also switched my programmer from a nRF52-DK PCA10040 board to a nRF5340-DK PCA10095 board. I made this switch because I was concerned that there may have been confusion between the nRF52832 on my programmer, and the nRF52832 on my custom hardware. I am not sure if this made a difference or not.

When I plugged in my nRF5340-DK, I was prompted in VS Code to update the firmware on the device. I followed the prompt and a firmware update was installed. Unsure if that is relevant.

Note: the RTT/SWD interface is shared by the flashing operation and RTT logging. It seems that reflashing the board causes the RTT logs to freeze up. I need to manually kill the RTT terminal and reopen it every time I flash. But, I am getting my printk's and log messages now.

Thank you to Kazi for helping me.

Setting up console over SWD interface

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