multi connection problem - peripheral

[Kyu]

Hello Nordics.

I developed a device that display a navigation information using s110 (nRF51822)

My device receive the road information by an application.

But, when I test my device using Samsung Galaxy S3, and if I use other BT device (hands-free), disconnection occurred.

In short, when I use 2 peripheral Bluetooth device (hands-free and my device (navigation thing), data transmission delay occurs, and 2 peripherals are disconnected.

After that, my device cannot connect with Samsung Galaxy S3.

I think, it is a Samsung Galaxy S3's OS problem. (I didn't see this problem with other phones)

But is there any solution that can maintain stable multi-connection? I guess, I may make it stable by changing some connection parameter values.

This is my connection parameter values.

MIN_CONN_INTERVAL : MSEC_TO_UNITS(30, UNIT_1_25_MS)
MAX_CONN_INTERVAL : MSEC_TO_UNITS(200, UNIT_1_25_MS)
SLAVE_LATENCY : 0
CONN_SUP_TIMEOUT : MSEC_TO_UNITS(300, UNIT_10_MS)
FIRST_CONN_PARAMS_UPDATE_DELAY : APP_TIMER_TICKS(5000, APP_TIMER_PRESCALER) NEXT_CONN_PARAMS_UPDATE_DELAY : APP_TIMER_TICKS(30000, APP_TIMER_PRESCALER)
MAX_CONN_PARAMS_UPDATE_COUNT : 3

[Pål Håland]

Hi Kyu,

I see that you have set the

CONN_SUP_TIMEOUT = MSEC_TO_UNITS(300, UNIT_10_MS);

But this should in fact be at least (1 + Conn_Latency) * Conn_Interval_Max * 2 See Bluetooth Core 4.2 - Volume 2, Part E, 7.8.12.

The reason why it works on other phones might be how their controller select the connection interval to use.

[Kyu]

Thank you so mush Pal Haland.

I changed the connection interval to Min: 7.5ms Max: 10ms Connection supervisor timeout : 300

But this problem still exist.

Are there other suggestions?

[Pål Håland]

I would try to increase the min and max conn interval instead, as this would give the phone more time to fit all the different connections. 10 ms is not that much when streaming audio. Other than that I have nothing else I can think of.

[Kyu]

Thanks. I will try~!