增加blinky example,修改信号量limit

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

project(blinky)

target_sources(app PRIVATE src/main.c)

.. zephyr:code-sample:: blinky

   :name: Blinky

   :relevant-api: gpio_interface

   Blink an LED forever using the GPIO API.

Overview

********

The Blinky sample blinks an LED forever using the :ref:`GPIO API <gpio_api>`.

The source code shows how to:

#. Get a pin specification from the :ref:`devicetree <dt-guide>` as a

   :c:struct:`gpio_dt_spec`

#. Configure the GPIO pin as an output

#. Toggle the pin forever

See :zephyr:code-sample:`pwm-blinky` for a similar sample that uses the PWM API instead.

.. _blinky-sample-requirements:

Requirements

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

Your board must:

#. Have an LED connected via a GPIO pin (these are called "User LEDs" on many of

   Zephyr's :ref:`boards`).

#. Have the LED configured using the ``led0`` devicetree alias.

Building and Running

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

Build and flash Blinky as follows, changing ``reel_board`` for your board:

.. zephyr-app-commands::

   :zephyr-app: samples/basic/blinky

   :board: reel_board

   :goals: build flash

   :compact:

After flashing, the LED starts to blink and messages with the current LED state

are printed on the console. If a runtime error occurs, the sample exits without

printing to the console.

Build errors

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

You will see a build error at the source code line defining the ``struct

gpio_dt_spec led`` variable if you try to build Blinky for an unsupported

board.

On GCC-based toolchains, the error looks like this:

.. code-block:: none

   error: '__device_dts_ord_DT_N_ALIAS_led_P_gpios_IDX_0_PH_ORD' undeclared here (not in a function)

Adding board support

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

To add support for your board, add something like this to your devicetree:

.. code-block:: DTS

   / {

   	aliases {

   		led0 = &myled0;

   	};

   	leds {

   		compatible = "gpio-leds";

   		myled0: led_0 {

   			gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;

                };

   	};

   };

The above sets your board's ``led0`` alias to use pin 13 on GPIO controller

``gpio0``. The pin flags :c:macro:`GPIO_ACTIVE_HIGH` mean the LED is on when

the pin is set to its high state, and off when the pin is in its low state.

Tips:

- See :dtcompatible:`gpio-leds` for more information on defining GPIO-based LEDs

  in devicetree.

- If you're not sure what to do, check the devicetrees for supported boards which

  use the same SoC as your target. See :ref:`get-devicetree-outputs` for details.

- See :zephyr_file:`include/zephyr/dt-bindings/gpio/gpio.h` for the flags you can use

  in devicetree.

- If the LED is built in to your board hardware, the alias should be defined in

  your :ref:`BOARD.dts file <devicetree-in-out-files>`. Otherwise, you can

  define one in a :ref:`devicetree overlay <set-devicetree-overlays>`.

CONFIG_GPIO=y

sample:

  name: Blinky Sample

tests:

  sample.basic.blinky:

    tags:

      - LED

      - gpio

    filter: dt_enabled_alias_with_parent_compat("led0", "gpio-leds")

    depends_on: gpio

    harness: led

    integration_platforms:

      - frdm_k64f

/*

 * Copyright (c) 2016 Intel Corporation

 *

 * SPDX-License-Identifier: Apache-2.0

 */

#include <stdio.h>

#include <zephyr/kernel.h>

#include <zephyr/drivers/gpio.h>

/* 1000 msec = 1 sec */

#define SLEEP_TIME_MS   1000

/* The devicetree node identifier for the "led0" alias. */

#define LED0_NODE DT_ALIAS(led0)

/*

 * A build error on this line means your board is unsupported.

 * See the sample documentation for information on how to fix this.

 */

static const struct gpio_dt_spec led = GPIO_DT_SPEC_GET(LED0_NODE, gpios);

int main(void)

{

	int ret;

	bool led_state = true;

	if (!gpio_is_ready_dt(&led)) {

		return 0;

	}

	ret = gpio_pin_configure_dt(&led, GPIO_OUTPUT_ACTIVE);

	if (ret < 0) {

		return 0;

	}

	while (1) {

		ret = gpio_pin_toggle_dt(&led);

		if (ret < 0) {

			return 0;

		}

		led_state = !led_state;

		printf("LED state: %s\n", led_state ? "ON" : "OFF");

		k_msleep(SLEEP_TIME_MS);

	}

	return 0;

}