applications: nrf_desktop: Add dongle_small config for nRF52833 DK

Change introduces `dongle_small` configuration for nRF52833 DK. The
configuration is used to debug memory-tailored configurations used by
dongles with small SoCs.

Jira: NCSDK-31675

Signed-off-by: Marek Pieta <[email protected]>
Signed-off-by: Divya Pillai <[email protected]>

Author: MarekPieta

applications/nrf_desktop/board_configuration.rst

@@ -65,8 +65,11 @@ Sample mouse, keyboard or dongle (``nrf52840dk/nrf52840``)
 Sample dongle (``nrf52833dk/nrf52833``)
       * The configuration uses the nRF52833 Development Kit.
       * The application is configured to act as a dongle that forwards data from both mouse and keyboard.
-      * Bluetooth uses Nordic Semiconductor's SoftDevice link layer and is configured to act as a central.
+        The dongle acts as a Bluetooth central.
         Input data comes from Bluetooth and is retransmitted to USB.
+      * For most of the build types, Bluetooth uses Nordic Semiconductor's SoftDevice link layer.
+      * The ``dongle_small`` configuration enables logs and mimics the dongle configuration used for small SoCs.
+        The configuration is used to verify the correct behavior of the memory-tailored configurations.
       * The configuration with the MCUboot bootloader is set as default.
 
 Sample dongle (``nrf52833dk/nrf52820``)

applications/nrf_desktop/configuration/nrf52833dk_nrf52833/app_dongle_small.overlay

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/ {
+	chosen {
+		zephyr,bt-hci = &bt_hci_controller;
+	};
+
+	/* Configure DTS nodes used for USB next HID support. */
+	hid_dev_0: hid_dev_0 {
+		compatible = "zephyr,hid-device";
+		interface-name = "HID0";
+		protocol-code = "none";
+		in-polling-period-us = <1000>;
+		in-report-size = <64>;
+	};
+	hid_dev_1: hid_dev_1 {
+		compatible = "zephyr,hid-device";
+		interface-name = "HID1";
+		protocol-code = "none";
+		in-polling-period-us = <1000>;
+		in-report-size = <64>;
+	};
+
+	gpioled0 {
+		compatible = "gpio-leds";
+		status = "okay";
+		label = "LED System State";
+
+		led0_g: led_0 {
+			gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;
+			label = "Green LED 0";
+		};
+	};
+
+	gpioled1 {
+		compatible = "gpio-leds";
+		status = "okay";
+		label = "LED Peer State";
+		led1_g: led_1 {
+			gpios = <&gpio0 14 GPIO_ACTIVE_LOW>;
+			label = "Green LED 1";
+		};
+
+	};
+	leds {
+		status = "disabled";
+	};
+};
+
+
+&usbd {
+	compatible = "nordic,nrf-usbd";
+	status = "okay";
+	num-bidir-endpoints = <0>;
+	num-in-endpoints = <4>;
+	num-out-endpoints = <2>;
+	num-isoin-endpoints = <0>;
+	num-isoout-endpoints = <0>;
+};
+
+&bt_hci_controller {
+	status = "okay";
+};
+
+&bt_hci_sdc {
+	status = "disabled";
+};

applications/nrf_desktop/configuration/nrf52833dk_nrf52833/images/mcuboot/prj_dongle_small.conf

@@ -0,0 +1,61 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_SIZE_OPTIMIZATIONS=y
+
+CONFIG_HW_STACK_PROTECTION=y
+
+CONFIG_SYSTEM_CLOCK_NO_WAIT=y
+
+CONFIG_MAIN_STACK_SIZE=10240
+CONFIG_MBEDTLS_CFG_FILE="mcuboot-mbedtls-cfg.h"
+
+CONFIG_BOOT_BOOTSTRAP=n
+
+CONFIG_FLASH=y
+CONFIG_FPROTECT=y
+CONFIG_BOOT_ERASE_PROGRESSIVELY=y
+CONFIG_SOC_FLASH_NRF_EMULATE_ONE_BYTE_WRITE_ACCESS=y
+
+# Serial
+CONFIG_CONSOLE=n
+CONFIG_SERIAL=y
+CONFIG_UART_CONSOLE=n
+CONFIG_UART_NRFX=n
+CONFIG_UART_INTERRUPT_DRIVEN=y
+
+# MCUBoot serial
+CONFIG_GPIO=y
+CONFIG_GPIO_NRFX_INTERRUPT=n
+CONFIG_MCUBOOT_SERIAL=y
+CONFIG_BOOT_SERIAL_CDC_ACM=y
+CONFIG_BOOT_SERIAL_UART=n
+
+# Required by USB
+CONFIG_MULTITHREADING=y
+
+# USB
+CONFIG_USB_DEVICE_MANUFACTURER="Nordic Semiconductor ASA"
+CONFIG_USB_DEVICE_PRODUCT="Bootloader nRF52 Desktop"
+CONFIG_USB_DEVICE_VID=0x1915
+CONFIG_USB_DEVICE_PID=0x52DF
+CONFIG_USB_DEVICE_STACK=y
+CONFIG_USB_DEVICE_REMOTE_WAKEUP=n
+CONFIG_USB_CDC_ACM=y
+
+# Decrease memory footprint
+CONFIG_CBPRINTF_NANO=y
+CONFIG_UART_USE_RUNTIME_CONFIGURE=n
+CONFIG_UART_LINE_CTRL=n
+CONFIG_TIMESLICING=n
+CONFIG_BOOT_BANNER=n
+CONFIG_NCS_BOOT_BANNER=n
+
+# Use minimal C library instead of the Picolib
+CONFIG_MINIMAL_LIBC=y
+
+# Improve firmware reliability
+CONFIG_RESET_ON_FATAL_ERROR=y

applications/nrf_desktop/configuration/nrf52833dk_nrf52833/pm_static_dongle_small.yml

@@ -0,0 +1,25 @@
+mcuboot:
+  address: 0x0
+  size: 0xd000
+mcuboot_pad:
+  address: 0xd000
+  size: 0x200
+app:
+  address: 0xd200
+  size: 0x70e00
+mcuboot_primary:
+  orig_span: &id001
+  - mcuboot_pad
+  - app
+  span: *id001
+  address: 0xd000
+  size: 0x71000
+mcuboot_primary_app:
+  orig_span: &id002
+  - app
+  span: *id002
+  address: 0xd200
+  size: 0x70e00
+settings_storage:
+  address: 0x7e000
+  size: 0x2000

applications/nrf_desktop/configuration/nrf52833dk_nrf52833/prj_dongle_small.conf

@@ -0,0 +1,93 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+################################################################################
+# dongle_small: Dongle on small SoC version (with logs)
+#
+# The configuration mimics dongle configuration for small SoCs by using SW Split
+# link layer and enabling memory consumption optimizations. The configuration
+# also enables logs to simplify debugging.
+# Application Configuration
+
+CONFIG_DESKTOP_INIT_LOG_MOTION_EVENT=n
+CONFIG_DESKTOP_INIT_LOG_HID_REPORT_EVENT=n
+CONFIG_DESKTOP_INIT_LOG_HID_REPORT_SENT_EVENT=n
+CONFIG_CAF_INIT_LOG_KEEP_ALIVE_EVENTS=n
+
+CONFIG_CAF_BUTTONS=y
+CONFIG_CAF_BUTTONS_POLARITY_INVERSED=y
+CONFIG_CAF_BUTTONS_PM_KEEP_ALIVE=n
+
+CONFIG_CAF_CLICK_DETECTOR=y
+
+CONFIG_CAF_LEDS=y
+
+CONFIG_DESKTOP_ROLE_HID_DONGLE=y
+CONFIG_DESKTOP_DEVICE_PID=0x52E1
+
+CONFIG_DESKTOP_BLE_PEER_CONTROL=y
+CONFIG_DESKTOP_BLE_PEER_CONTROL_BUTTON=0x0000
+CONFIG_DESKTOP_BLE_NEW_PEER_SCAN_REQUEST=y
+CONFIG_DESKTOP_BLE_NEW_PEER_SCAN_ON_BOOT=y
+CONFIG_DESKTOP_BLE_PEER_ERASE=y
+
+CONFIG_DESKTOP_CONFIG_CHANNEL_ENABLE=y
+
+################################################################################
+# Zephyr Configuration
+
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
+CONFIG_ISR_STACK_SIZE=1280
+CONFIG_MAIN_STACK_SIZE=840
+CONFIG_IDLE_STACK_SIZE=128
+CONFIG_BT_HCI_TX_STACK_SIZE_WITH_PROMPT=y
+CONFIG_BT_HCI_TX_STACK_SIZE=1536
+
+# Reuse system workqueue as Bluetooth RX context to reduce memory consumption
+CONFIG_BT_RECV_WORKQ_SYS=y
+
+CONFIG_BOOT_BANNER=n
+CONFIG_NCS_BOOT_BANNER=n
+
+CONFIG_NUM_COOP_PRIORITIES=10
+CONFIG_NUM_PREEMPT_PRIORITIES=11
+CONFIG_TIMESLICING=n
+
+CONFIG_HEAP_MEM_POOL_SIZE=1024
+
+CONFIG_SYS_CLOCK_TICKS_PER_SEC=1000
+CONFIG_SYSTEM_CLOCK_NO_WAIT=y
+
+CONFIG_HW_STACK_PROTECTION=y
+CONFIG_RESET_ON_FATAL_ERROR=n
+
+CONFIG_GPIO=y
+
+CONFIG_REBOOT=y
+
+CONFIG_SIZE_OPTIMIZATIONS=y
+
+CONFIG_LED=y
+CONFIG_LED_GPIO=y
+
+CONFIG_USB_NRFX_EVT_QUEUE_SIZE=16
+
+CONFIG_BT_PRIVACY=y
+CONFIG_BT_LL_SW_SPLIT=y
+
+# Optimize Bluetooth controller for size to reduce memory consumption
+CONFIG_BT_CTLR_ADVANCED_FEATURES=y
+CONFIG_BT_CTLR_OPTIMIZE_FOR_SIZE=y
+
+CONFIG_BT_BUF_ACL_TX_SIZE=35
+CONFIG_BT_CTLR_DATA_LENGTH_MAX=35
+CONFIG_BT_ATT_TX_COUNT=6
+
+################################################################################
+
+CONFIG_ASSERT=y
+CONFIG_ASSERT_LEVEL=2
+
+CONFIG_DESKTOP_LOG=y

applications/nrf_desktop/configuration/nrf52833dk_nrf52833/sysbuild_dongle_small.conf

@@ -0,0 +1,11 @@
+#
+# Copyright (c) 2025 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+################################################################################
+
+SB_CONFIG_BOOTLOADER_MCUBOOT=y
+SB_CONFIG_MCUBOOT_MODE_SINGLE_APP=y
+SB_CONFIG_BOOT_SIGNATURE_TYPE_RSA=y
+SB_CONFIG_BOOT_SIGNATURE_KEY_FILE="\${APPLICATION_CONFIG_DIR}/images/mcuboot/mcuboot_private.pem"

applications/nrf_desktop/sample.yaml

@@ -68,6 +68,12 @@ tests:
     integration_platforms:
       - nrf52840dk/nrf52840
     extra_args: FILE_SUFFIX=wwcb
+  applications.nrf_desktop.zdebug_dongle_small:
+    build_only: true
+    platform_allow: nrf52833dk/nrf52833
+    integration_platforms:
+      - nrf52833dk/nrf52833
+    extra_args: FILE_SUFFIX=dongle_small
   applications.nrf_desktop.zdebug_fast_pair.gmouse.uart.kmu_provision:
     platform_allow:
       - nrf54l15dk/nrf54l10/cpuapp

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -242,6 +242,8 @@ nRF Desktop
   * Application configurations for the nRF54L05 and nRF54L10 SoCs (emulated on the nRF54L15 DK).
     The configurations are supported through ``nrf54l15dk/nrf54l10/cpuapp`` and ``nrf54l15dk/nrf54l05/cpuapp`` board targets.
     For details, see the :ref:`nrf_desktop_board_configuration`.
+  * The ``dongle_small`` configuration for the nRF52833 DK.
+    The configuration enables logs and mimics the dongle configuration used for small SoCs.
 
 nRF Machine Learning (Edge Impulse)
 -----------------------------------

scripts/quarantine_integration.yaml

@@ -514,6 +514,12 @@
     - nrf52840dk/nrf52840
   comment: "Configurations excluded to limit resources usage in integration builds"
 
+- scenarios:
+    - applications.nrf_desktop.zdebug_dongle_small
+  platforms:
+    - nrf52833dk/nrf52833
+  comment: "Configurations excluded to limit resources usage in integration builds"
+
 - scenarios:
     - applications.nrf_desktop.zdebug_3bleconn
     - applications.nrf_desktop.zrelease_4llpmconn