Node-RED MCU用のノードを作成してみる　その3（Serialノード）

2024年4月11日 2024年7月12日

管理人

はじめに

　今回はNode-RED MCU用のSerialノードを作成してみました。デバッガツールとは元々シリアル通信を行っているのですが、他のポートでのシリアル通信を行うことができます。

　なお、今回作成したノードはnpmやGitHubに公開しています。Node-REDのパレットの管理からインストールすることもできます。

▼npmでのページはこちら

https://www.npmjs.com/package/@background404/node-red-contrib-mcu-serial

▼GitHubでのページはこちら

https://github.com/404background/node-red-contrib-mcu-serial

記事ではバージョン0.2.0の内容になっています。
Peter Hoddieさんからissueに報告を頂きまして、現在機能を追加中です。
最新版はリポジトリをご覧ください。
https://github.com/404background/node-red-contrib-mcu-serial/issues/1
https://github.com/404background/node-red-contrib-mcu-serial/issues/3

▼以前の記事はこちら

▼Node-REDとNode-RED MCUの簡単な紹介はこちら

functionノードでの動作確認

　Node-RED MCUメンバーの方々が、funcitonノードでのSerialクラスの検証をされていました。その記事がありますので、詳細はそちらをご覧ください。

　私も記事を参考にプログラムを書き込んだところ、動作していました。

▼こちらの記事です。

https://qiita.com/NWLab/items/5360eff7b8e2685e925a

https://qiita.com/mshioji/items/a750a5d713ab4d54c4cf

　Moddable SDKのドキュメントにも、Serialクラスのサンプルプログラムがあります。

▼コールバックやプロパティについてはこちらをご覧ください。

https://github.com/Moddable-OpenSource/moddable/blob/public/documentation/io/io.md#serial

　コールバックの中にonReadable()があります。シリアル通信で受信したときの処理を、このonReadable()に記述します。

ノードを作成する

ファイル構成

　主なファイルは以下の5つです。

package.json：Node-REDで読み込むファイルの指定
manifest.json：Node-RED MCUで読み込むファイルの指定
node/mcu_serial.js：Node-REDでの機能の設定
node/mcu_serial.html：Node-REDでの表示の設定
node/serial.js：マイコンに書き込むプログラムの設定

▼図示するとこんな感じです。

　ちなみに、mcu_serial.jsにserial.jsの内容を記述すると、Node-RED側でエラーが出てビルドできません。Moddable SDKのクラスが含まれているからです。これを回避するために、ファイルを分けています。

　また、このファイル構成は、node-red-mcuリポジトリのi2cノードの構成を参考にしています。i2cノードにはinとoutの二種類が用意されており、今回のSerialノードもinとoutを用意します。

▼i2cノードはこちら

https://github.com/phoddie/node-red-mcu/tree/main/nodes/mcu/i2c

　pwmノードが分かりやすいのですが、クラスの宣言が重複しないようにcacheに値をセットするようになっています。Serialノードを作成するときも同じ仕組みを適用していたのですが、Serial inとSerial outでファイルを分けているとcacheが共有されていないようでした。Serialクラスはすでに宣言されているというエラーが出ていました。

　i2cノードに倣って、１つのファイルにまとめると解決しました。

▼pwmノードはこちら

https://github.com/phoddie/node-red-mcu/blob/main/nodes/mcu/pwm/pwm.js

moddable_manifestについて

　これまではnode_types.jsonにmanifest.jsonを追加する必要がありました。ユーザーにとって使いにくいのが懸念されていたのですが、htmlファイルにmoddable_manifestを加えることで回避する仕組みがあるようです。

▼Xでコメントを頂きました。

This is very cool. Congratulations! The instructions require editing node_types.json. You may be able to eliminate that step by including "moddable_manifest" in the JSON exported by your Node-RED editor plug-in. Please see here: https://t.co/BIo4XO8SeK
— Peter Hoddie (@phoddie) March 27, 2024

▼こちらで議論されていたようです。

https://github.com/phoddie/node-red-mcu/discussions/106#discussioncomment-5434299

　そのことを踏まえて、プログラムにmoddable_manifestを追加しています。他の部分は、ピン番号やポート、ボーレートなどの数値を入力するようになっています。

▼プログラムはこちら

<script type="text/javascript">
    RED.nodes.registerType('mcu_serial_in',{
        category: 'MCU',
        color: '#a2aaff',
        defaults: {
            name: {value:""},
            tx: {value:"", required: true},
            rx: {value:"", required: true},
            baud: {value: "115200"},
            port: {value: "", required: true},
            moddable_manifest: {
                value: {
                    include: [
                        {
                            "git": "https://github.com/404background/node-red-contrib-mcu-serial.git"
                        }
                    ]
                }
            }
        },
        inputs: 0,
        outputs: 1,
        icon: "serial.svg",
		align: "left",
        paletteLabel: 'Serial in',
        label: function() {
            return this.name||"serial in"
        }
    })
</script>

<script type="text/javascript">
    RED.nodes.registerType('mcu_serial_out',{
        category: 'MCU',
        color: '#a2aaff',
        defaults: {
            name: {value:""},
            tx: {value:"", required: true},
            rx: {value:"", required: true},
            baud: {value: "115200"},
            port: {value: "", required: true},
            moddable_manifest: {
                value: {
                    include: [
                        {
                            "git": "https://github.com/404background/node-red-contrib-mcu-serial.git"
                        }
                    ]
                }
            }
        },
        inputs: 1,
        outputs: 0,
        icon: "serial.svg",
		align: "right",
        paletteLabel: 'Serial out',
        label: function() {
            return this.name||"serial_out"
        }
    })
</script>


<script type="text/html" data-template-name="mcu_serial_in">
    <div class="form-row">
        <label for="node-input-name"><i class="fa fa-tag"></i> Name</label>
        <input type="text" id="node-input-name" placeholder="Name"><br>
        <label for="node-input-tx"><i class="fa fa-tag"></i> TX</label>
		<input type="number" id="node-input-tx" style="width:60px"><br>
        <label for="node-input-rx"><i class="fa fa-tag"></i> RX</label>
		<input type="number" id="node-input-rx" style="width:60px"><br>
        <label for="node-input-port"><i class="fa fa-tag"></i> Port</label>
		<input type="number" id="node-input-port" style="width:60px"><br>
        <label for="node-input-baud"><i class="fa fa-tag"></i> Baud</label>
		<input type="number" id="node-input-baud" style="width:100px"><br>
    </div>
</script>

<script type="text/html" data-template-name="mcu_serial_out">
    <div class="form-row">
        <label for="node-input-name"><i class="fa fa-tag"></i> Name</label>
        <input type="text" id="node-input-name" placeholder="Name"><br>
        <label for="node-input-tx"><i class="fa fa-tag"></i> TX</label>
		<input type="number" id="node-input-tx" style="width:60px"><br>
        <label for="node-input-rx"><i class="fa fa-tag"></i> RX</label>
		<input type="number" id="node-input-rx" style="width:60px"><br>
        <label for="node-input-port"><i class="fa fa-tag"></i> Port</label>
		<input type="number" id="node-input-port" style="width:60px"><br>
        <label for="node-input-baud"><i class="fa fa-tag"></i> Baud</label>
		<input type="number" id="node-input-baud" style="width:100px"><br>
    </div>
</script>

serial.jsについて

　issueにて報告を頂きまして、複数のノードを配置した場合にも対応できるよう修正しました。Serial_inクラス、Serial_outクラスでSerialクラスのaddを呼び出しています。

　また、ハイライトしている10行目の部分で、Serialクラスを呼び出しています。

▼プログラムはこちら

import {Node} from "nodered"
let cache

class Serial {
	static add(config, reader) {
		const cachePort = 'mcu_serial' + Number(config.port);
		cache ??= new Map;
		let serial = cache.get(cachePort);
		if (!serial) {
			serial = new device.io.Serial({
				baud: Number(config.baud),
				port: Number(config.port),
				receive: Number(config.rx),
				transmit: Number(config.tx),
				onReadable() {
					let msg = String.fromArrayBuffer(this.read());
					msg = msg.trimEnd()
					this.readers.forEach(reader => {
						reader.send({payload: msg})
					});
				}
			})
			cache.set(cachePort, serial)
			serial.readers = [];
		}
		if (reader)
			serial.readers.push(reader);
		return serial;
	}
}

class Serial_in extends Node {
	onStart(config) {
		super.onStart(config)

		try {
			Serial.add(config, this);
		}
		catch {
			this.status({fill: "red", shape: "dot", text: "node-red:common.status.error"})
		}
	}

	static type = "mcu_serial_in"
	static {
		RED.nodes.registerType(this.type, this)
	}
}


class Serial_out extends Node {
	#serial

	onStart(config) {
		super.onStart(config)

		try {
			this.#serial = Serial.add(config);
		}
		catch {
			this.status({fill: "red", shape: "dot", text: "node-red:common.status.error"})
		}
	}

	onMessage(msg, done) {
		if (msg.payload != null){
			this.#serial.write(ArrayBuffer.fromString(msg.payload + "\n"))
		}
		this.send(msg)
		done()
	}

	static type = "mcu_serial_out"
	static {
		RED.nodes.registerType(this.type, this)
	}
}

その他のファイル

　他のファイルはシンプルな内容になっています。

▼mcu_serial.jsはこちら。ノードを作成しています。

module.exports = function(RED) {
    function Serial_in(config) {
        RED.nodes.createNode(this, config)
		console.log(config)
    }
    RED.nodes.registerType("mcu_serial_in", Serial_in)

    function Serial_out(config) {
        RED.nodes.createNode(this, config)
		console.log(config)
    }
    RED.nodes.registerType("mcu_serial_out", Serial_out)
}

▼manifest.jsonはこちら。serial.jsの位置を指定しています。

{
	"modules": {
		"mcu_serial": "./node/serial"
	},
	"preload": "mcu_serial"
}

ローカル環境にインストールする

　Node-REDのpackage.jsonがあるディレクトリで、以下のコマンドを実行すると、作成したノードをインストールすることができます。


 npm install フォルダのパス

▼categoryはMCUにしているので、Node-RED MCU pluginのノードに並んで追加されます。

▼実際に並べるとこんな感じ。

▼ノードの編集画面では、ピン番号やポート、ボーレートを入力できるようになっています。

動作確認

　Raspberry Pi 400のUSB端子にUART変換器を挿し、マイコンのピンと接続しました。

▼UART変換器はこちらと同じタイプです。

https://amzn.to/3VxTpQM

　マイコンのピン指定は以下の通りです。

Port2
- TX:17
- RX:16
Port1
- TX:32
- RX:33

▼Moddable TwoとESP32の開発ボードで検証しました。

　Raspberry Pi 400のNode-REDでSerial inノードとSerial outノードを配置し、通信してみました。

▼ちゃんと通信できているようです。

▼複数のノード、ポートでも試してみたところ、ちゃんと動作していました。

▼サンプルフローはこちら

[{"id":"c89a7915711bfdeb","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":290,"y":280,"wires":[["8b1fa7b8a67af26b"]]},{"id":"339b61347fce7654","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":560,"y":320,"wires":[]},{"id":"c2ecbb9ad97eb951","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":290,"y":240,"wires":[["3e015ac89dd2d7c7"]]},{"id":"2a8a61ef546a55a5","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":560,"y":360,"wires":[]},{"id":"29b69e6ea1d47b25","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":560,"y":440,"wires":[]},{"id":"ac9bc3d9e001354c","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":560,"y":480,"wires":[]},{"id":"876dad9e9d96429e","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":290,"y":200,"wires":[["b9bd6be923e97f86"]]},{"id":"acea8e5c05d25374","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"17","rx":"16","baud":"115200","port":"2","_mcu":{"mcu":true},"x":290,"y":160,"wires":[["9277468d9337d91c"]]},{"id":"d2c338a2a7c651a7","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":560,"y":740,"wires":[]},{"id":"4ac79b2549d24954","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":290,"y":580,"wires":[["d29834a11cc8e2ad"]]},{"id":"e21beb58cbcd545f","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":560,"y":780,"wires":[]},{"id":"371bcdb0d5ebb8f0","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":560,"y":860,"wires":[]},{"id":"e4eb27aab5762f9f","type":"mcu_serial_out","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":560,"y":900,"wires":[]},{"id":"305d1470cfcd1b67","type":"comment","z":"2eb8ae4cb799d590","name":"Port 1","info":"","_mcu":{"mcu":true},"x":150,"y":580,"wires":[]},{"id":"6f42bcd6ce0555eb","type":"comment","z":"2eb8ae4cb799d590","name":"Port 2","info":"","_mcu":{"mcu":true},"x":150,"y":160,"wires":[]},{"id":"3d6157a653b67692","type":"inject","z":"2eb8ae4cb799d590","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"one","payloadType":"str","_mcu":{"mcu":true},"x":290,"y":320,"wires":[["339b61347fce7654"]]},{"id":"177c2c3449b7cf91","type":"inject","z":"2eb8ae4cb799d590","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"two","payloadType":"str","_mcu":{"mcu":true},"x":290,"y":360,"wires":[["2a8a61ef546a55a5","339b61347fce7654"]]},{"id":"65ae2dc4ee97c76a","type":"inject","z":"2eb8ae4cb799d590","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"four","payloadType":"str","_mcu":{"mcu":true},"x":290,"y":480,"wires":[["ac9bc3d9e001354c","29b69e6ea1d47b25","2a8a61ef546a55a5","339b61347fce7654"]]},{"id":"c5f1494b658b3189","type":"inject","z":"2eb8ae4cb799d590","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"two","payloadType":"str","_mcu":{"mcu":true},"x":290,"y":780,"wires":[["d2c338a2a7c651a7","e21beb58cbcd545f"]]},{"id":"d9f4cd3b754be5c0","type":"inject","z":"2eb8ae4cb799d590","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"one","payloadType":"str","_mcu":{"mcu":true},"x":290,"y":740,"wires":[["d2c338a2a7c651a7"]]},{"id":"ea5592c8964b4472","type":"inject","z":"2eb8ae4cb799d590","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"four","payloadType":"str","_mcu":{"mcu":true},"x":290,"y":900,"wires":[["d2c338a2a7c651a7","e21beb58cbcd545f","371bcdb0d5ebb8f0","e4eb27aab5762f9f"]]},{"id":"8b1fa7b8a67af26b","type":"debug","z":"2eb8ae4cb799d590","name":"Port2 4","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":280,"wires":[]},{"id":"3e015ac89dd2d7c7","type":"debug","z":"2eb8ae4cb799d590","name":"Port2 3","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":240,"wires":[]},{"id":"b9bd6be923e97f86","type":"debug","z":"2eb8ae4cb799d590","name":"Port2 2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":200,"wires":[]},{"id":"9277468d9337d91c","type":"debug","z":"2eb8ae4cb799d590","name":"Port2 1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":160,"wires":[]},{"id":"3c1959db7312756a","type":"debug","z":"2eb8ae4cb799d590","name":"Port0 4","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":700,"wires":[]},{"id":"b417cd6de3aa689b","type":"debug","z":"2eb8ae4cb799d590","name":"Port0 3","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":660,"wires":[]},{"id":"4fa1b84c726a7d14","type":"debug","z":"2eb8ae4cb799d590","name":"Port0 2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":620,"wires":[]},{"id":"d29834a11cc8e2ad","type":"debug","z":"2eb8ae4cb799d590","name":"Port0 1","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","statusVal":"","statusType":"auto","_mcu":{"mcu":true},"x":440,"y":580,"wires":[]},{"id":"d6bd987f16963f4e","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":290,"y":620,"wires":[["4fa1b84c726a7d14"]]},{"id":"5e44451b2d96f012","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":290,"y":660,"wires":[["b417cd6de3aa689b"]]},{"id":"1041e276a55d5f3d","type":"mcu_serial_in","z":"2eb8ae4cb799d590","name":"","tx":"32","rx":"33","baud":"115200","port":"1","_mcu":{"mcu":true},"x":290,"y":700,"wires":[["3c1959db7312756a"]]}]

▼動作はこんな感じです。