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Smart Bluetooth Forum Discussions

Anonymous
Not applicable

We have a custom board using BCM20736S running a modified Heart Rate Monitor App.

Everything is working pretty well and we are sending data to the iPhone 4 times per second.

The connection interval in this example is 250 msec.

Normally the connection events are around 10 mAmp as seen on the scope.

Fairly often we see a timeout disconnect (code 08) but the system usually reconnects promptly with no issues.

All too often though we are seeing a spontaneous system reboot which is preceded briefly by rapid rise in the current used during each connection event.  The current rises until it reaches the extraordinary level of 30 mAmp and then the system reboots itself.

The system is able to reconnect but this is very undesirable behavior.  Not only does it take considerable power (battery drain) if it happens repeatedly, but each time we lose some data.

I wonder if anybody else has seen similar behavior and maybe has a clue what might be causing this.

See image attached.  The tall current peaks are connection events.  Each major division on the vertical axis is about 10 mAmp. Each major division on the horizontal axis is 500 milliseconds.  Normally the connection events appear like the ones at the left side, typically between 8 and 15 mAmp.

Thanks for any info,

Eric.

Reboot.jpg

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1 Solution
Anonymous
Not applicable

I  changed the supervisor timeout to a lower number and now the system does not reboot. Presumably it was the high current draw that triggered the reboot and a shorter timeout prevents the connection event currents from reaching too high.

I still end up with a disconnect and reconnect but at least the system does not reboot. I suspect the frequent disconnects might be due to application processing interfering with the connection events, but I don't know if that's possible.

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Anonymous
Not applicable

I  changed the supervisor timeout to a lower number and now the system does not reboot. Presumably it was the high current draw that triggered the reboot and a shorter timeout prevents the connection event currents from reaching too high.

I still end up with a disconnect and reconnect but at least the system does not reboot. I suspect the frequent disconnects might be due to application processing interfering with the connection events, but I don't know if that's possible.

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Thanks for reporting the resolution to the forum Eric.  I honestly was not sure where to start on this one.

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