Bluetooth - data reading from custom controller returning same value - ios

Question

I am creating app which connects to custom controller and reads some data over bluetooth, should be pretty simple stuff.
App has address and data characteristics:
- I am writing addresses to address characteristics (that way I tell controller which values from given addresses I would like to have)
- Controller is updating data characteristics with values from given addresses
I am constantly updating address in time interval of 12 seconds to receive different values from different addresses.
App works and is reading data from controller. But after some time values on data address don't update and controller returns same values for different addresses.
We know controller works since Android version of the app has already been made and it works like a charm.
I am wondering if anyone has any idea what could be wrong? Is there a way bluetooth connection changes services / characteristics so I have to update them too?
EDIT
Wasn't able to add code before, so here is the main part:
To sum it up:
I read values manually by using .readValue and .writeWithResponse when writing.
internal func nextIteration() {
if _writeQueue.count > 0 {
self.writeData()
} else {
self.readData()
}
}
internal func writeData() {
let writeProperty = _writeQueue[0]
self.writeDataCharacteristics(writeProperty: writeProperty)
_writeQueue.remove(at: 0)
}
internal func readData() {
if _resetReadParameters || _currentPropertiesNumber != _selectedPropertiesNumber {
if _selectedPropertiesNumber >= _readQueue.count || _selectedPropertiesNumber < 0 {
_selectedPropertiesNumber = 0
}
_currentProperties = _readQueue[_selectedPropertiesNumber]
writeAddressCharacteristics()
_resetReadParameters = false
_currentPropertiesNumber = _selectedPropertiesNumber
return
}
readDataCharacteristics()
_selectedPropertiesNumber += 1
if _selectedPropertiesNumber >= _readQueue.count {
_selectedPropertiesNumber = 0
}
}
internal func writeAddressCharacteristics() {
if _currentProperties.count != Constants.maxProperties {
print("Not enough current properties.")
return
}
_addressBytes.removeAll()
for property in _currentProperties {
let a = property.address.rawValue
_addressBytes.append(UInt8(a & 0xFF))
_addressBytes.append(UInt8(a >> 8))
}
peripheral?.writeValue(Data(bytes: _addressBytes), for: _address, type: .withResponse)
}
internal func writeDataCharacteristics(writeProperty: Property) {
_writeBytes?.removeAll()
let d = UInt16(bitPattern: Int16(writeProperty.value!))
_writeBytes = [UInt8(d & 0xFF), UInt8(d >> 8), 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]
peripheral?.writeValue(Data(bytes: _writeBytes!), for: _data, type: .withResponse)
}
internal func readDataCharacteristics() {
_communicatingData = true
peripheral?.readValue(for: _data)
}
internal func parseValueBroadcast(bytes: [UInt8], property: Property, byteIndex: Int) {
let value = Int(Int16(bitPattern: UInt16(bytes[byteIndex]) | UInt16(bytes[byteIndex + 1]) << 8))
property.value = value
_communicationDelegate?.didReceiveProperty(property: property)
}
internal func setWriteProperty(address: Address, value: Int) {
let newProperty = Property.get(address)
newProperty.value = value
_writeQueue.append(newProperty)
if _pausedReading {
nextIteration()
}
}
// MARK: CBPeripheralDelegate
func peripheral(_ peripheral: CBPeripheral, didWriteValueFor characteristic: CBCharacteristic, error: Error?) {
if let writeError = error {
print("Error writing: \(writeError.localizedDescription)")
}
DispatchQueue.main.asyncAfter(deadline: .now() + 4, execute: {
self.nextIteration()
})
}
func peripheral(_ peripheral: CBPeripheral, didUpdateValueFor characteristic: CBCharacteristic, error: Error?) {
if let error = error {
print("READ ERROR:", error.localizedDescription)
return
}
guard let value = characteristic.value else {
print("READ ERROR: NO DATA")
return
}
let bytes = [UInt8](value)
if !_pausedReading {
var n = 0
for property in _currentProperties {
parseValueBroadcast(bytes: bytes, property: property, byteIndex: n)
n += 2
}
}
DispatchQueue.main.asyncAfter(deadline: .now() + 4, execute: {
self.nextIteration()
})
}
}