We are going to use QN9021 for our application development and we have the following questions about the IC:
1. Where can I find the reference design for RF matching network and antenna?
2. Where can I find the IDE tool and SDK and related documents for BLE application development?
3. We need to use the SWD interface as well as the ADC interface (they share the same IO pins). Any reference design for this?
4. The VREF of ADC is programmable: how can we set this parameter?
5. 32k external crystal is optional. If we decide to use the internal oscillator, what kind settings do we need to change?