CODEWITHSUNDEEP
swiftios8core-bluetooth
Zalak Patel
Zalak Patel

Reputation: 1965

Amount of data to be sent to peripheral using bluetooth in ios 8

I am working in data transferring using bluetooth from BLE device to peripheral hardware. I want to write data from binary file in chunks as total data length is 143233. I found one line "Maximal MTU was 132 bytes for iOS 7 devices and 20 B for iOS 6" but what about iOS 8? What will be maximum size of chunks for iOS 8? This is the code which I have used, I dont know whether i am going right way or not so help me and guide me if i am going wrong. Thanks in advance.

var count:Int = 0
var counter:Int = 0
var str:NSString = NSBundle.mainBundle().pathForResource("spp", ofType: "bin")!
println("string value is \(str)")     
var dataFile:NSString = NSString.stringWithContentsOfFile(str, encoding: NSASCIIStringEncoding, error: nil)
data = dataFile.dataUsingEncoding(NSUTF8StringEncoding)
println(data!.length)
println(dataFile.length)
var dataLen:Int = data!.length
if (dataLen > 132)
   {
      while(count < dataLen && dataLen - count > 132)
        {
          peripheral.writeValue(data!.subdataWithRange(NSMakeRange(count, 132)), forCharacteristic: arrCharacteristics!.objectAtIndex(1) as CBCharacteristic , type: CBCharacteristicWriteType.WithResponse)
           NSThread.sleepForTimeInterval(0.005)
           println("Write performed \(counter++ )")
                   count += 132
                }
            }   if (count < dataLen)
 {
   peripheral.writeValue(data!.subdataWithRange(NSMakeRange(count, dataLen - count)), forCharacteristic: arrCharacteristics!.objectAtIndex(1) as CBCharacteristic , type: CBCharacteristicWriteType.WithResponse)
 }

Upvotes: 1

Views: 1076

Answers (1)

Buzzwig
Buzzwig

Reputation: 460

I'm guessing Jalek found his answer but for anyone else seeking the figures.

iOS 7 requests a 135 byte MTU (132 bytes data + 3 overhead).

iOS 8 requests a 158 byte MTU (155 bytes data + 3 overhead).

Obviously, it will depend on the other device whether these values are accepted or a lower value returned.

Upvotes: 2

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