samples: boards: espressif: ulp: Add interrupt sample

Add an interrupt triggered by HP Core sample

Signed-off-by: Lucas Tamborrino <lucas.tamborrino@espressif.com>

samples/boards/espressif/ulp/lp_core/interrupt_ulp/CMakeLists.txt

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+# Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+set(REMOTE_ZEPHYR_DIR ${CMAKE_CURRENT_BINARY_DIR}/../interrupt_ulp_lpcore/zephyr)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+
+message(STATUS "${CONFIG_BOARD_TARGET} compile as Master in this sample")
+project(interrupt_ulp_hpcore)
+
+target_sources(app PRIVATE src/main.c)

samples/boards/espressif/ulp/lp_core/interrupt_ulp/Kconfig.sysbuild

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+# Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+source "share/sysbuild/Kconfig"
+
+config ULP_REMOTE_BOARD
+	string
+	default "esp32c6_devkitc/esp32c6/lpcore" if $(BOARD) = "esp32c6_devkitc"

samples/boards/espressif/ulp/lp_core/interrupt_ulp/README.rst

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+.. zephyr:code-sample:: interrupt-ulp
+   :name: Interrupt ULP
+
+   HP Core interrupt LP Core.
+
+Overview
+********
+
+This sample shows how to trigger LP Core interrupt from the HP core.
+
+Building and Flashing
+*********************
+
+Build the sample code as follows:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/boards/espressif/ulp/lp_core/interrupt_ulp
+   :board: esp32c6_devkitc/esp32c6/hpcore
+   :west-args: --sysbuild
+   :goals: build
+   :compact:
+
+Flash it to the device with the command:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/boards/espressif/ulp/lp_core/interrupt_ulp
+   :board: esp32c6_devkitc/esp32c6/hpcore
+   :west-args: --sysbuild
+   :goals: flash
+   :compact:
+
+Sample Output
+=============
+
+Console output on the HP core:
+
+.. code-block:: console
+
+    Triggering ULP interrupt...
+    Triggering ULP interrupt...
+    Triggering ULP interrupt...
+    Triggering ULP interrupt...
+    Triggering ULP interrupt...
+
+Console output on the LP core:
+
+.. code-block:: console
+
+    LP PMU interrupt received: 0
+    LP PMU interrupt received: 1
+    LP PMU interrupt received: 2
+    LP PMU interrupt received: 3
+    LP PMU interrupt received: 4

samples/boards/espressif/ulp/lp_core/interrupt_ulp/app.overlay

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+/*
+ * Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&lp_uart {
+	status = "okay";
+};

samples/boards/espressif/ulp/lp_core/interrupt_ulp/prj.conf

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+CONFIG_ULP_COPROC_ENABLED=y

samples/boards/espressif/ulp/lp_core/interrupt_ulp/remote/CMakeLists.txt

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+# Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+
+message(STATUS "${BOARD} compiles as remote in this sample")
+project(interrupt_ulp_lpcore)
+
+target_sources(app PRIVATE src/main.c)

samples/boards/espressif/ulp/lp_core/interrupt_ulp/remote/prj.conf

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+# nothing here

samples/boards/espressif/ulp/lp_core/interrupt_ulp/remote/src/main.c

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+/*
+ * Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include "ulp_lp_core_utils.h"
+#include "ulp_lp_core_interrupts.h"
+
+volatile uint32_t lp_core_pmu_intr_count;
+
+void ulp_lp_core_lp_pmu_intr_handler(void)
+{
+	ulp_lp_core_sw_intr_clear();
+	lp_core_pmu_intr_count++;
+	printf("LP PMU interrupt received: %d\n", lp_core_pmu_intr_count);
+}
+
+int main(void)
+{
+	lp_core_pmu_intr_count = 0;
+	ulp_lp_core_intr_enable();
+	ulp_lp_core_sw_intr_enable(true);
+
+	while (1) {
+		/* Wait forever, handling interrupts */
+		asm volatile("wfi");
+	}
+	return 0;
+}

samples/boards/espressif/ulp/lp_core/interrupt_ulp/sample.yaml

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+sample:
+  name: ESP32-C6 LP_CORE Interrupt Sample
+tests:
+  sample.boards.espressif.ulp.lp_core.interrupt_ulp:
+    platform_allow:
+      - esp32c6_devkitc/esp32c6/hpcore
+    tags:
+      - samples
+    sysbuild: true

samples/boards/espressif/ulp/lp_core/interrupt_ulp/src/main.c

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+/*
+ * Copyright (c) 2025 Espressif Systems (Shanghai) Co., Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <ulp_lp_core.h>
+#include <zephyr/kernel.h>
+
+int main(void)
+{
+	while (1) {
+		printf("Triggering ULP interrupt...\n");
+		ulp_lp_core_sw_intr_trigger();
+		k_sleep(K_MSEC(1000));
+	}
+
+	return 0;
+}

samples/boards/espressif/ulp/lp_core/interrupt_ulp/sysbuild.cmake

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+# SPDX-License-Identifier: Apache-2.0
+#
+# Copyright 2024 Espressif
+
+# Add external project
+ExternalZephyrProject_Add(
+    APPLICATION interrupt_ulp_lpcore
+    SOURCE_DIR ${APP_DIR}/remote
+    BOARD ${SB_CONFIG_ULP_REMOTE_BOARD}
+  )
+
+# Add dependencies so that the remote sample will be built first
+# This is required because some primary cores need information from the
+# remote core's build, such as the output image's LMA
+add_dependencies(interrupt_ulp interrupt_ulp_lpcore)
+sysbuild_add_dependencies(CONFIGURE interrupt_ulp interrupt_ulp_lpcore)
+sysbuild_add_dependencies(FLASH interrupt_ulp_lpcore interrupt_ulp)
+
+if(SB_CONFIG_BOOTLOADER_MCUBOOT)
+  # Make sure MCUboot is flashed first
+  sysbuild_add_dependencies(FLASH interrupt_ulp mcuboot)
+endif()