BLE Stack v1.3 & iOS Connection Stability

Ben Scammell

Other Parts Discussed in Thread: CC2540

Folks,

Is there a complete list of things to do to ensure connection stability between the CC2540 (DK-MINI) and an Apple iOS device (iOS 6)?

My setup all works, but I get more than a few random diconnects, which is just not apporpriate for what I'm doing.

All help appreciated, and we can use this thread to create a reference list which TI can upload to the Wiki at some point to help others.

Cheers in advance!

Ben

over 12 years ago

0 Hermann Menning over 12 years ago

Expert 1305 points

I also am very much interested in this matter.

0 Ben Scammell over 12 years ago in reply to Hermann Menning

Intellectual 620 points

Anyone?

0 Jay Yeh over 12 years ago

Intellectual 465 points

Hi Ben,

I am now working on this.

The connections with iOS devices are troublesome.

So I would hope there's an official example from TI for BLE stack v1.3.

Could you also provide your settings so that members could check them?

0 Ben Scammell over 12 years ago in reply to Jay Yeh

Intellectual 620 points

What settings would you like?

0 Jay Yeh over 12 years ago in reply to Ben Scammell

Intellectual 465 points

Like the connection parameters. I thinks these are matter to make connections with iOS devices(correct me if I am wrong).

DEFAULT_ADVERTISING_INTERVAL

DEFAULT_ENABLE_UPDATE_REQUEST

DEFAULT_DESIRED_MIN_CONN_INTERVAL

DEFAULT_DESIRED_MAX_CONN_INTERVAL

DEFAULT_DESIRED_SLAVE_LATENCY

DEFAULT_DESIRED_CONN_TIMEOUT

0 Ben Scammell over 12 years ago in reply to Jay Yeh

Intellectual 620 points

Are these in the firmware or iOS?

0 Ben Scammell over 12 years ago in reply to Jay Yeh

Intellectual 620 points

My setting (which should be default)

DEFAULT_ADVERTISING_INTERVAL = (I can't find ANY refererence to this)

DEFAULT_ENABLE_UPDATE_REQUEST = FALSE

DEFAULT_DESIRED_MIN_CONN_INTERVAL = 80

DEFAULT_DESIRED_MAX_CONN_INTERVAL = 800

DEFAULT_DESIRED_SLAVE_LATENCY = 0

DEFAULT_DESIRED_CONN_TIMEOUT = 1000

0 tylerw over 12 years ago in reply to Ben Scammell

Intellectual 555 points

https://developer.apple.com/hardwaredrivers/BluetoothDesignGuidelines.pdf

Check out the Bluetooth Low Energy section.

-Tyler

0 Ben Scammell over 12 years ago in reply to tylerw

Intellectual 620 points

Thanks.

Relevant bits:-

Interval Max * (SlaveLatency + 1 ≤ 2seconds)

Interval Min ≥ 20ms

Interval Min + 20ms ≤ Interval Max

Slave Latency ≤ 4

connSupervisionTimeout ≤ 6seconds

IntervalMax * (SlaveLatency + 1) * 3 < connSupervisionTimeout

So from that can anyone suggest any figures?

0 Ben Scammell over 12 years ago in reply to Ben Scammell

Intellectual 620 points

I mean, the defaults fit those criteria, but is there anthing better that results in a more stable connection?

0 Hermann Menning over 12 years ago in reply to Ben Scammell

Expert 1305 points

It seems you are using a connSupervisionTimeout larger than 6 seconds (1000) try using a value of 600 or below.

0 Ben Scammell over 12 years ago in reply to Hermann Menning

Intellectual 620 points

I feel stupid now! :-)

Testing with...

DEFAULT_ADVERTISING_INTERVAL = (I can't find ANY refererence to this)

DEFAULT_ENABLE_UPDATE_REQUEST = FALSE

DEFAULT_DESIRED_MIN_CONN_INTERVAL = 80

DEFAULT_DESIRED_MAX_CONN_INTERVAL = 800

DEFAULT_DESIRED_SLAVE_LATENCY = 0

DEFAULT_DESIRED_CONN_TIMEOUT = 500

0 Jun Feng Hu over 12 years ago in reply to Ben Scammell

Prodigy 230 points

I test it in Keyfob with stack 1.3.0

DEFAULT_DESIRED_MIN_CONN_INTERVAL = 80

DEFAULT_DESIRED_MAX_CONN_INTERVAL = 800

DEFAULT_DESIRED_SLAVE_LATENCY = 0

DEFAULT_DESIRED_CONN_TIMEOUT = 600

I used iOS6.1.4 with iphone5

But iphone5 will lose connection with keyfob.

Anybody know why lose connection?

0 Prashant Vaibhav over 12 years ago in reply to Ben Scammell

Intellectual 370 points

Some time back I created a Numbers spreadsheet inside which you can input the connection parameters you plan to use, and the spreadsheet tells you whether all Apple criteria are satisfied or not. If not, it also gives suggestions on what to change.

I've attached the Numbers spreadsheet (as a zip file) and also a converted Excel spreadsheet.

Change only the "Value" column of "Connection Parameters" worksheet. Hope this helps.

2538.Bluetooth Connection Parameter Test.zip

0458.Bluetooth Connection Parameter Test.xls

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BLE Stack v1.3 & iOS Connection Stability