How transfer more 20 bits in mtu max 23

[dmsuh]

Describe the bug
How to send data in 20 bits?
I can't implement it.
Bluetooth version 4.0 on connected device
max 23 mtu on connected device

To Reproduce
code Vue js

const delay = ms => new Promise(res => setTimeout(res, ms));
const dataVal = new Uint8Array([
  0xAB, 0x05, 0x02, 0x00, 0x80, 0x00, 0x20, 0xD1, 0xDB, 0x00, 0x08, 0x4F, 0x06, 0x01, 0x08, 0x19,
  0xDC, 0x00, 0x08, 0x51, 0x06, 0x01, 0x08, 0x53, 0x06, 0x01, 0x08, 0x55, 0x06, 0x01, 0x08, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0xDC,
  0x00, 0x08, 0x57, 0x06, 0x01, 0x08, 0x00, 0x00, 0x00, 0x00, 0x19, 0xDC, 0x00, 0x08, 0xC9, 0xC3,
  0x00, 0x08, 0xED
]);
const packetVal = ref(<Uint8Array[]>[])

async function sendPackets() {
  // Determine the number of packets required based on the payload size and MTU
  const numPackets = Math.ceil(dataVal.length / 20);
  console.log(numPackets)

  for (let i = 0; i < numPackets; i++) {
    const packet = dataVal.subarray(i * 20, (i + 1) * 20);
    packetVal.value.push(packet)
    await delay(1000)

  }
}

async function sendF() {
  for (let i = 0; i < packetVal.value.length; i++) {
    await BleClient.writeWithoutResponse(
      idModem.value,
      numberToUUID(0xffe0),
      numberToUUID(0xffe1),
      new DataView(packetVal.value[i].buffer)
    );

  }
}
onMounted(async () => {
  await delay(5000)
  await sendPackets()
  await sendF()

Expected behavior
I would like to see a record of 20 bits of information
ab 05 02 00 80 00 20 d1 db 00 08 4f 06 01 08 19 dc 00 08 51 - the first packet
06 01 08 53 06 01 08 55 06 01 08 00 00 00 00 00 00 00 00 00 - the second package
00 00 00 00 00 00 00 19 dc 00 08 57 06 01 08 00 00 00 00 19 - third package
dc 00 08 c9 c3 00 08 ed - fourth package
but got DataView with same data

2023-10-06 22:45:58.052 29339-29339 Capacitor/Plugin        org.boon.ble                         V  To native (Capacitor plugin): callbackId: 81196753, pluginId: BluetoothLe, methodName: writeWithoutResponse
2023-10-06 22:45:58.054 29339-29339 Capacitor               org.boon.ble                         V  callback: 81196753, pluginId: BluetoothLe, methodName: writeWithoutResponse, methodData: {"deviceId":"D0:B5:C2:90:B4:4B","service":"0000ffe0-0000-1000-8000-00805f9b34fb","characteristic":"0000ffe1-0000-1000-8000-00805f9b34fb","value":"ab 05 02 00 80 00 20 d1 db 00 08 4f 06 01 08 19 dc 00 08 51 06 01 08 53 06 01 08 55 06 01 08 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 19 dc 00 08 57 06 01 08 00 00 00 00 19 dc 00 08 c9 c3 00 08 ed"}
2023-10-06 22:45:58.061 29339-29353 Device                  org.boon.ble                         D  resolve: write|0000ffe0-0000-1000-8000-00805f9b34fb|0000ffe1-0000-1000-8000-00805f9b34fb Characteristic successfully written.
2023-10-06 22:45:58.066 29339-29339 Capacitor/Console       org.boon.ble                         I  File: http://192.168.0.11:9500/ - Line 232 - Msg: undefined
2023-10-06 22:45:58.069 29339-29339 Capacitor/Plugin        org.boon.ble                         V  To native (Capacitor plugin): callbackId: 81196754, pluginId: BluetoothLe, methodName: writeWithoutResponse
2023-10-06 22:45:58.071 29339-29339 Capacitor               org.boon.ble                         V  callback: 81196754, pluginId: BluetoothLe, methodName: writeWithoutResponse, methodData: {"deviceId":"D0:B5:C2:90:B4:4B","service":"0000ffe0-0000-1000-8000-00805f9b34fb","characteristic":"0000ffe1-0000-1000-8000-00805f9b34fb","value":"ab 05 02 00 80 00 20 d1 db 00 08 4f 06 01 08 19 dc 00 08 51 06 01 08 53 06 01 08 55 06 01 08 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 19 dc 00 08 57 06 01 08 00 00 00 00 19 dc 00 08 c9 c3 00 08 ed"}
2023-10-06 22:45:58.080 29339-29380 GPUAUX                  org.boon.ble                         E  [AUX]GuiExtAuxCheckAuxPath:667: Null anb
2023-10-06 22:45:58.081 29339-29353 Device                  org.boon.ble                         D  resolve: write|0000ffe0-0000-1000-8000-00805f9b34fb|0000ffe1-0000-1000-8000-00805f9b34fb Characteristic successfully written.
2023-10-06 22:45:58.086 29339-29339 Capacitor/Console       org.boon.ble                         I  File: http://192.168.0.11:9500/ - Line 232 - Msg: undefined
2023-10-06 22:45:58.090 29339-29339 Capacitor/Plugin        org.boon.ble                         V  To native (Capacitor plugin): callbackId: 81196755, pluginId: BluetoothLe, methodName: writeWithoutResponse
2023-10-06 22:45:58.092 29339-29339 Capacitor               org.boon.ble                         V  callback: 81196755, pluginId: BluetoothLe, methodName: writeWithoutResponse, methodData: {"deviceId":"D0:B5:C2:90:B4:4B","service":"0000ffe0-0000-1000-8000-00805f9b34fb","characteristic":"0000ffe1-0000-1000-8000-00805f9b34fb","value":"ab 05 02 00 80 00 20 d1 db 00 08 4f 06 01 08 19 dc 00 08 51 06 01 08 53 06 01 08 55 06 01 08 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 19 dc 00 08 57 06 01 08 00 00 00 00 19 dc 00 08 c9 c3 00 08 ed"}
2023-10-06 22:45:58.098 29339-29353 Device                  org.boon.ble                         D  resolve: write|0000ffe0-0000-1000-8000-00805f9b34fb|0000ffe1-0000-1000-8000-00805f9b34fb Characteristic successfully written.
2023-10-06 22:45:58.099 29339-29380 GPUAUX                  org.boon.ble                         E  [AUX]GuiExtAuxCheckAuxPath:667: Null anb
2023-10-06 22:45:58.101 29339-29339 Capacitor/Console       org.boon.ble                         I  File: http://192.168.0.11:9500/ - Line 232 - Msg: undefined
2023-10-06 22:45:58.104 29339-29339 Capacitor/Plugin        org.boon.ble                         V  To native (Capacitor plugin): callbackId: 81196756, pluginId: BluetoothLe, methodName: writeWithoutResponse
2023-10-06 22:45:58.106 29339-29339 Capacitor               org.boon.ble                         V  callback: 81196756, pluginId: BluetoothLe, methodName: writeWithoutResponse, methodData: {"deviceId":"D0:B5:C2:90:B4:4B","service":"0000ffe0-0000-1000-8000-00805f9b34fb","characteristic":"0000ffe1-0000-1000-8000-00805f9b34fb","value":"ab 05 02 00 80 00 20 d1 db 00 08 4f 06 01 08 19 dc 00 08 51 06 01 08 53 06 01 08 55 06 01 08 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 19 dc 00 08 57 06 01 08 00 00 00 00 19 dc 00 08 c9 c3 00 08 ed"}
2023-10-06 22:45:58.114 29339-29353 Device                  org.boon.ble                         D  resolve: write|0000ffe0-0000-1000-8000-00805f9b34fb|0000ffe1-0000-1000-8000-00805f9b34fb Characteristic successfully written.
2023-10-06 22:45:58.117 29339-29339 Capacitor/Console       org.boon.ble                         I  File: http://192.168.0.11:9500/ - Line 232 - Msg: undefined

Screenshots

Plugin version:
"@capacitor-community/bluetooth-le": "^3.0.0"
"@capacitor/app": "^5.0.0",
"@capacitor/core": "^5.0.0",

[dmsuh]

this is only one Uint8Array, and it has a total of 1407 rows, need push by BLE

[pwespi]

Try something like

const dataVal = new Uint8Array([
  0xab, 0x05, 0x02, 0x00, 0x80, 0x00, 0x20, 0xd1, 0xdb, 0x00, 0x08, 0x4f, 0x06,
  0x01, 0x08, 0x19, 0xdc, 0x00, 0x08, 0x51, 0x06, 0x01, 0x08, 0x53, 0x06, 0x01,
  0x08, 0x55, 0x06, 0x01, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0xdc, 0x00, 0x08, 0x57, 0x06,
  0x01, 0x08, 0x00, 0x00, 0x00, 0x00, 0x19, 0xdc, 0x00, 0x08, 0xc9, 0xc3, 0x00,
  0x08, 0xed,
]);
const packetLength = 20;
const numPackets = Math.ceil(dataVal.length / packetLength);

for (let i = 0; i < numPackets; i++) {
  const dataView = new DataView(
    dataVal.slice(i * packetLength, (i + 1) * packetLength).buffer
  );
  await BleClient.writeWithoutResponse(
    idModem.value,
    numberToUUID(0xffe0),
    numberToUUID(0xffe1),
    dataView
  );
}

By using slice you get a part of the full buffer.

In your code, when you're calling dataVal.subarray(i * 20, (i + 1) * 20).buffer you get the full buffer back, which is not what you want.