``` <!DOCTYPE HTML> <html lang="ja"> <head> <meta charset="UTF-8"> <title></title> <script> const UUID_UART_SERVICE = '6e400001-b5a3-f393-e0a9-e50e24dcca9e' const UUID_TX_CHAR_CHARACTERISTIC = '6e400002-b5a3-f393-e0a9-e50e24dcca9e' const UUID_RX_CHAR_CHARACTERISTIC = '6e400003-b5a3-f393-e0a9-e50e24dcca9e' var targetDevice; let tx = null let rx = null var arrayData=[]; /// 接続 async function getMicrobit() { ///constは書き換えを禁止した変数を宣言するところ→１回決めたら変えれない /// デバイスのスキャン ///promise構文 const device = await navigator.bluetooth.requestDevice({ filters: [ { services: [UUID_UART_SERVICE] }, { namePrefix: 'BBC micro:bit' } ] }) /// GATT接続 targetDevice = device; const server=await device.gatt.connect(); const service=await server.getPrimaryService(UUID_UART_SERVICE); const characteristics=await Promise.all([ service.getCharacteristic(UUID_TX_CHAR_CHARACTERISTIC), service.getCharacteristic(UUID_RX_CHAR_CHARACTERISTIC)]) tx = characteristics[0]; rx = characteristics[1]; await tx.startNotifications(); await tx.addEventListener('characteristicvaluechanged', event=>{ var uint8=[]; uint8=DataView.prototype.getUint8(tx.value);//txのuint8配列要素を取り出したい console.log(uint8); arrayData = arrayData.concat(uint8); console.log(arrayData); //const text = new TextDecoder().decode(tx.value); //document.getElementById('getMessage').value = document.getElementById('getMessage').value+text; }) } /// 切断 function disconnect() { if (!targetDevice.gatt.connected){ return; } targetDevice.gatt.disconnect(); alert("切断しました。"); } //データを送る async function sendData(){ var startTime = performance.now(); const text=document.getElementById("sendText").value; const uint8=new TextEncoder().encode(text); for(let i=0;i<uint8.length;i+=19){ await rx.writeValue(uint8.subarray(i, i+19)); //UTF-8を返してpromiseを返す console.log(uint8.subarray(i, i+19)); } var endTime = performance.now(); console.log(endTime-startTime); } //テキストエリアのリセット function textClear(){ document.getElementById("getMessage").value=""; document.getElementById("sendText").value=""; var arrayData=[]; } </script> </head> <body> <div > <div id="BLE_button"> <input type="button" value="micro:bitと接続する" onclick="getMicrobit();"/> <input type="button" value="切断する" onclick="disconnect();"/> <textarea id ="sendText" name="text" rows="20" cols="40" ></textarea> <input type="button" value="送信する" onclick="sendData();"/> <textarea id="getMessage" name="name" rows="20" cols="40"></textarea> <input type="button" value="クリア" onclick="textClear();"> </div> </div> </body> </html> ```