Getting a BLE error trying to get Puck to talk to Bangle

Hey all, I'm a little lost here. My Bangle is running a watchface that is listening on a specific UUID for short strings to act as notifications (not BLE notifications, just messages). The Bangle code works fine, and I can access it from both a Web Bluetooth page and a DroidScript app. However, I can't get my puck to send the message properly. Here is the Bangle (peripheral) code snippet:

var BLEMessage = "";
NRF.setServices({
  "feb10001-f00d-ea75-7192-abbadabadebb": {
    "feb10002-f00d-ea75-7192-abbadabadebb": {
      value : [0],
      maxLen : 20,
      writable : true,
      onWrite : function(evt) {
        let str = stringFromArray(evt.data);
        if(str === "__EOM__") {
          if(BLEMessage) {
            showMsg('Message',BLEMessage);
          } else {
            reload();
            scheduleAlarms();
            showMsg('', 'Reloading...');
          }
          BLEMessage = '';
        } else {
          BLEMessage += str;
        }
      }
    }
  }
}, { });

The showMsg() function is defined and works fine (just draws a dialog box and writes the string to screen).

Here is the Puck code (mostly thanks to Gordon's BLE example):

const primaryServiceUuid = 'feb10001-f00d-ea75-7192-abbadabadebb';
const sendCharUuid = 'feb10002-f00d-ea75-7192-abbadabadebb';

let device, sendCharacteristic;


const split20 = (msg) => {
  let chunks = [];
  while(msg.length > 20) {
    chunks.push(msg.substr(0, 20));
    msg = msg.substr(20);
  }
  if(msg.length) chunks.push(msg);
  return chunks;
};

var msgToSend = "FOO!";
var logMsg = '';

function logD() {
  require("Storage").write('logMsg.txt', logMsg);
}

function sendMsg() {
  var gatt;
   NRF.requestDevice({  filters: [{ namePrefix: 'Bangle' }]  })
  .then(function(device) {
    logMsg += "Found\n";
    digitalPulse(LED2,1,10);
    return device.gatt.connect();
  }).then(function(g) {
    logMsg += "Connected\n";
    digitalPulse(LED3,1,10);
    gatt = g;
    return g.getPrimaryService(primaryServiceUuid);
  }).then(function(service) {
    logMsg += "got PS\n";
    return service.getCharacteristic(sendCharUuid);
  }).then(function(characteristic) {
    logMsg += "Got char\n";
    sendCharacteristic = characteristic;
    return sendCharacteristic.writeValue(toArrBuf(myMessage));
  }).then(function() {
    logMsg += "Sending: " + JSON.stringify(toArrBuf(myMessage));
    return sendCharacteristic.writeValue( toArrBuf('__EOM__'));
  }).then(function() {
    digitalPulse(LED2,1,[10,200,10,200,10]);
    gatt.disconnect();
    logMsg += "Done!\n";
    logD();
    busy=false;
  }).catch(function(e) {
    digitalPulse(LED1,1,10);
    logMsg += e.toString()+"\n";
    busy=false;
    logD();
  });
}


setWatch(sendMsg, BTN, {edge:"rising", debounce:50, repeat:true});

Which works fine in an HTML page using "let NRF = navigator.bluetooth;"
I'm writing my log to a file since console is disabled when I run this, and the file reads:

Found
Connected
BLE error 0x11 (BUSY)

As i said, I know the Bangle code works, been using it for weeks. The Puck code runs in a browser just fine. Which device is "BUSY"?? Any help appreciated!

Which device is "BUSY"??

I guess it is bluetoooth stack on Puck that is BUSY - the return g.getPrimaryService(primaryServiceUuid); fail for some reason. Could it be that this code is running multiple times or there is something else BLE related running on Puck at the same time?

Hi! I'm pretty sure you've his exactly this issue that was reported a few days ago: http://forum.espruino.com/conversations/363920/#comment15998892

I have no idea why this has happened yet but I will look into it very soon. For the moment you can almost certainly fix it by changing:

    return device.gatt.connect();
  }).then(function(g) {
    logMsg += "Connected\n";
    digitalPulse(LED3,1,10);
    gatt = g;
    return g.getPrimaryService(primaryServiceUuid);
  }).then(function(service) {

to:

    return device.gatt.connect();
  }).then(function(g) {
    logMsg += "Connected\n";
    digitalPulse(LED3,1,10);
    gatt = g;
    return new Promise(r => setTimeout(r,500)); //< ---------- added this delay
  }).then(function() {
    return gatt.getPrimaryService(primaryServiceUuid);
  }).then(function(service) {
...

Thank you @Gordon!! That was it! And thanks for forwarding the other issue, I did a search on the forums for BLE Error 11 and I get no hits (not even this post).

And @fanoush... thank you too! You have inspired me to order both an F07 and a DK08 to flash into Espruinos. I'm trying to work up the courage to make a build for PineTime. It's been a LONG time since i've worked at device level (hence my preference for JS on MCUs) but you've done considerable heavy lifting already. I've learned a lot from you both!

Just to add I tried to reproduce this with recent firmware, but can't. I wonder whether there's something about the Bangle.js's configuration that's non-standard (like having bonding enabled somehow?).

Ok, I figured it out (I think). This is due to negotiation of a higher MTU since this was added in Espruino 2v09.

I think if you're connecting to a device with an older firmware you can connect just fine. It's when you connect between two devices with 2v09+ firmware that you have the issue. Follow this on the GitHub issue.

I did a search on the forums for BLE Error 11 and I get no hits (not even this post).

you need to turn off Title matched search terms filter which is preselected