Compiler/CC2640R2F: IOS device gets frequently disconnected on CC2640 eval board with simple peripheral application.

Hi Manisha, 

Which iOS version are you using? Have you made any modifications to the simple_peripheral application?

Thanks, 
Elin

Can you please provide me suggestions regarding this issue!

Hi Manisha, 

Have you made any modifications to the simple_peripheral project?

Which iOS application are you using? 

Thanks, 
Elin

Project Name: Quin Sensor

Annual Qty: 15k

We have not done any changes from BLE side, added accelerometer sensor and gyrometer sensor.

Hi Team,

Please find the attached images for recorded information about this specific issue(disconnecting in ios) using sniffer tool. But we are unable to find out why that behaviour is seen.Can you help in finding out the same.

IOS_Capture.psd

Hi Manisha,

Thanks for the update.

There is a newer version of the SDK available here: http://www.ti.com/tool/SIMPLELINK-CC2640R2-SDK
Do you see the same issue when you are testing with the latest version of the SDK?

Thanks, 
Elin

Hi Elin,

On this (simplelink_cc2640r2_sdk_2_30_00_28)  sdk version ,We have implemented our business logic and power management stuff. As we are planning for production for 15k units ,at this point of time migrating to newer version is not feasible.

Looking forward for the solution with sdk_2_30_00_28 version. But, we can check with this newer version. 

Hi Manisha,

Thanks for the clarification. 

Have you tried using another BLE scanner app? Are you using the same app for both android and ios?

When does the ios phone disconnects from the device? Does it happen at the same place every time?

Thanks, 
Elin

Hi Elin,

We have tried with other BLE apps( BLE scanner and also BLE Hero) and we used same app for both android and ios.

NEW UPDATE:

Please find the attachment for the new sniffing log which have been recorded today .

Nokia2.psd

Device has been checked with android,ios

observation in android: 

• When the device is kept nearer, ACK status is OK and it is connected always .
• When the device is kept little far, ACK status is RETRY for 2 or 3 times and then getting OK.The device is staying connected.
• when the device is moving far, we observe the ACK status as RETRY and after continuous RETRY, it is getting disconnected. We are getting FCE error before disconnection.

Can you please suggest me the reasons for this specific observation.Can you please prioritise this, as the device is for production. Thank you!

Hi Manisha, 

At what distance do you measure the "far" and a "little far"? Are you testing in a busy area?

I'm looking through the sniffer log you attached, and I'll try and reproduce the issue. 

Thanks, 
Elin

near => 1 or 2 feet

little far => 10 feet

far=> 20 feet

we are testing in our office, not much busy area.Can we know what happens if testing is done in busy area?

Can you also provide a sniffer log where it works as expected?

I tried to reproduce the issue using the pre-built simple_peripheral file using the LightBlue app on an iPhone, but I managed to stay in the connection even when walking approx 20 m from the Launchpad. Can you try and comment out the code you have added to the project and see if you still can reproduce the issue? If no, can you add the accelerometer and the gyroscope one by one to see which of them are causing the problem? 

Thanks, 
Elin

Hi Elin,

Please find the below sniffer log, where device works as expected.If you observe this log, we are not getting any RETRY from master continuously, always the communication is perfect.This is tested within 2 feets. We are expecting the same scenario with long distance as well.

expectedconnectivity.psd

Hi Manisha, 

Thanks for the log. 

Did you perform the tests I suggested in my previous post? What was the result, were you able to reproduce the issue using the simple_peripheral project without modifications?

Thanks, 
Elin

Hi Elin,

We are debugging ,could not find out the reason for this disconnection.

I just want to know is there any specifications regarding connection parameters?

If yes, what are those!

Hi Manisha,

Did you test with the default simple_peripheral application and see if you see the same issue as I mentioned in my previous posts?

Like I mentioned before, I don't see this issue when testing with the pre-built simple_peripheral hex file, so it would be interesting to know if you see the same issue when using the simple_peripheral project without modifications. 

Thanks,
Elin

Hi Elin,

Have tested with pre-built simple_peripheral hex file and didn't find this issue and we have been debugging by disabling extra features which were added , indeed could not find the reason behind .Part of debugging , want to know whether connection parameters effect this communication which leads to disconnection.

Hi Manisha, 

I'm glad to hear that you were able to make it work using the prebuilt simple_peripheral project!

Did you try adding one task at the time? First, doing everything related to the accelerometer and having everything with the gyroscope commented out, and then commenting out everything with the accelerometer and doing everything related to the gyroscope. What did you see? 

Please refer to the User's Guide for more information about the connection parameters.

Thanks, 
Elin

Hi Elin,

Have been debugging with all the possible ways.As you said i enabled each interrupt at a time and tested it, suprisingly it stays connected.Somewhere i feel that the more interrupts at a time is causing issue.so, to resolve this i want to disable rest of the interrupts while isr is handling the interrupt.For this task to be done, Can you suggest me changes i need to do .

Please suggest me if any clue regarding this.Thankyou!

Hi Manisha,

Did you debug using the ROV? See this section of the User's Guide for more information: http://dev.ti.com/tirex/explore/content/simplelink_cc2640r2_sdk_3_30_00_20/docs/blestack/ble_user_guide/html/ble-stack-3.x-guide/debugging-index.html#ti-rtos-object-viewer

Thanks, 
Elin

Hi Elin, 

 The code looks stable with android device now, but could not get the same stability with ios device. What could be the reason for this !

When testing with ios device , we get "error: The connection has timed out unexpectedly".

Assuming it could be issue with connection parameters, have changed them and checked for stability but could not achieve it.

If it is issue with connection parameters,Can you please suggest me the exact parameters which gives stability both with android device and also ios device.

If not, what are the reasons for this specific issue!

Hi Manisha, 

Did you check with ROV, as I mentioned in my previous post? It would be interesting to see if you have enough stack to support both tasks. 

Which connection parameters are you using now? How many combinations of connection parameters did you test, and what was the result with each parameter? 

Thanks, 
Elin

Hi Ellin,

Couldn't try with ROV as my device is completely enclosed.Not able to connect debug probe to device.

Three different combinations have been tried by me(this has been tried to increase stability in ios)

ADVERTISING_INTERVAL                      152.5

MIN_CONN_INTERVAL                            12

MAX_CONN_INTERVAL                           24

SLAVE_LATENCY                                     0

CONN_TIMEOUT                                      500

SBP_PERIODIC_EVT_PERIOD               600

//////////////////////////////////////////////////////////////////////////

No stability observed using these

ADVERTISING_INTERVAL                      152.5

MIN_CONN_INTERVAL                            16

MAX_CONN_INTERVAL                           80

SLAVE_LATENCY                                     1

CONN_TIMEOUT                                      550

/////////////////////////////////////////////////////////////////////////

This default combination is giving stability in android but little less in ios.

ADVERTISING_INTERVAL                      160

MIN_CONN_INTERVAL                            8

MAX_CONN_INTERVAL                           8

SLAVE_LATENCY                                     0

CONN_TIMEOUT                                     1000

SBP_PERIODIC_EVT_PERIOD               600

Hi Elin,

Disconnect issue using,

Android device : got resolved, could get stability

IOS device : still issue exists,but far better than before.

This is achieved by handling interrupts properly in the code. Disabling the specific interrupt when it is in ISR and enabling it when the periodic task gets executed.