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Original question:

CC2640: How to modify the LMP Response time?

CC2640R2F: BLE error code 0x22 (LL RESPONSE TIMEOUT)

William T
Intellectual 870 points
Part Number: CC2640R2F


Hi Marie,

Referring to your respond posted on Nov 27, 2017 (above), which is quoted below:

Since this is BLE the error message is 0x22: LL (Link Layer) RESPONSE TIMEOUT (not LMP, which is not part of the Bluetooth Low Energy mode).

There is a known issue for several android devices that they do not handle LL_LENGTH_REQ gracefully (not an issue in the TI BLE stack, but an issue in the android device). If you are using data length extensions this may be what you are seeing, you can try turning of DLE.

[Q1]: does TI have any details about this known issue on android device ?   any article / document or application notes about this ?

[Q2]: is it confirm that the root cause of the 0x22 (LL RESPONSE TIMEOUT) due to the DLE ?   is therre any other (possible) causes ?

Thank you in advance.

  • 0
    TI__Guru* 82861 points
    Hi William,

    1) This mainly regards older smart phone devices that do not support Bluetooth 4.2. (Data length extensions feature). If the smart phone device receives a LL_LENGTH_REQ it will stop reacting/spam meaningless packets etc. Extepcted response: Feature not supported but the connection can continue. We have seen this with LG Nexus 6.

    2) In the thread you have linked this is the cause, and disabling DLE in the slave device will remove this bug. However in general anytime a device does not respond to a LL request you will get an LL RESPONSE TIMEOUT.
  • 0 in reply to Marie H
    TI__Guru* 82861 points
    BTW we have taken some steps to try to alieveate the problem, if you are seeing this can you try to update to the newest SDK (Simplelink CC2640R2 2.30 SDK)?