Hi Sebastian and thank you for the reply, I was able to work through some of the difficulties, except for one main issue, which has to do with pending a callback function call inside an ISR.
I am using the QN9090DK with the latest SDK and have constructed a project exemplifying the issue I'm facing, based on the wireless UART example project (RTOS version).
Basically I am setting up a PWM to drive the ACD which has its ISR called every 1 second. I need to broadcast some data over BLE when the ISR is hit, so I'm using App_PostCallbackMessage to issue a pending callback (the callback would be BleApp_FlushUartStream), but using PostCallbackMessage hangs the system... stepping into it, I witnessed that actually gets hung internally on a call to xQueueSendFromISR, which is documented to be safe to use from within ISRs...).
Kind help would be appreciated.. as using pending callbacks correctly from within ISR is crucial to understand.
Thanks,
Sharon