Hello,
We are in process of FCC certification and we would like to use LTE and Bluetooth Coexistence to reduce number of measurement needed for the certification.
We are aware of SoftDevice support for the coexistence, we would like to use zephyr Opensource Bluetooth controller. We are willing to help with the Opensource implementation on the controller side. However to do so we encountered an issue. There is a large gap in documentation of the COEX pin functionality. So there are several questions i would like you to clarify.
- COEX0 functionality - Input to the LTE modem from external device.
- Does this effect only Transmission or also Receiving ?
- Is it currently implemented inside the Modem firmware ?
- Diagram shows on COEX0 State x State y State z, What exactly does that mean ? It is single GPIO which can only be 'one', 'zero' or 'high impedance' ?
- COEX2 functionality - Shows the pin in '1' during whole operation of the LTE Modem.
- How does it cycle when the modem is NOT using PSM ? Doest it even cycle to allow Bluetooth to operate ?
- Is the COEX2 active during LTE receiving ? I found later that indeed the COEX can be setup using AT Command. This resolve this question
- Can the timing of the COEX2 pin some how combine with '4 – COEX2 pin toggling enabled, TX indicator. Pin ON when RF is transmitting.' ? What is the default timing for this option "as late as possible timing, approximately 50–100 μs anticipation."?
Maybe you could give us an insight into operation of the coexistence in SoftDevice controller to help us.
