CC2540 Connection Error after multiple Connects / Disconnects

Seth Berggren

Other Parts Discussed in Thread: CC2540

Hello,

I have encountered an error with our prototype that I am currently trying to fix. The error occurs with connection and disconnection events. I am using a Bluetooth LE App called "BLE Scan" to connect to our LE Accessory (CC2540 based). The "BLE Scan" App basically acts as the "central" device that our "peripheral" device connects to.

The first attempt to connect the App to the Device is successful almost 100% of the time. But after disconnecting and then reconnecting (sometimes takes 3 to 4 tries before the error occurs), the Device will not properly handle the connection, it will cease advertising, and it cannot be connected to anymore until the power is cycled.

Essentially, the App thinks that it is connected to the Device, and the Device does not think that it is connected. This can also happen vice versa: I use the App to disconnect, and the App thinks that it is disconnected but the Device thinks that it is still connected.

I will be troubleshooting the Packet Sniffer logs in the coming days but would appreciate any help on the subject.

Thanks,

Seth Berggren

over 11 years ago

0 Eng351 over 11 years ago

Genius 4125 points

I have seen this type of error occur when the stack is not given enough time to process. Do you have any tasks that take more than a few ms to complete?

0 Seth Berggren over 11 years ago in reply to Eng351

Intellectual 910 points

Yes, I have several SPI communication events that take 8 ms to complete. The SPI is bit bang right now although I do have plans to implement it with the USART in the future to make it faster.

0 Eng351 over 11 years ago in reply to Seth Berggren

Genius 4125 points

You definatley should use the USART hardware and either USE ISR/DMA or at the very least minimise the number of bytes sent by any blocking function before allowing BLE stack to run

0 Seth Berggren over 11 years ago in reply to Eng351

Intellectual 910 points

I implemented the USART SPI. It seemed to improve the performance of my device (less connection errors), but I am still getting them. It turns out, the cause of these errors is my frequent changing of the advertising parameters with the GAP_UpdateAdvertisingData() command. When I don't periodically use this function, I get no errors whatsoever.

Thanks,

Seth

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CC2540 Connection Error after multiple Connects / Disconnects