Another engineer said I can use BLUENRG-M2SA as a processor and not just a slave. E closed documentation says it has an I2C bus and GPIO, which is good enough for me to complete the board. I have no idea on how to program this device without another microcontroller on the PCB.

 

Yes you can. It has a

• High performance, ultra-low power Cortex-M0 32-bit based core
• Programmable embedded 256 kB Flash
• 24 kB embedded RAM with data retention

It also has a pre-programmed UART bootloader.
In other words, conceptually, bring out the UART TxD/RxD & Gnd to header, plug in a USB serial device and load up the appropriate development environment on your PC. You can use STM's own, or they appear to support the Arduino IDE. So depending on what you need there appear to be various options. STM have a full IDE and a wide range of modular libraries for different application areas but I'll guess they aren't all free. If all you want to do is talk to a sensor via I2C, check/wiggle some input/outputs on GPIO and send/receive stuff on BT you may be able to do that with just the Arduino IDE and the data sheet/register map.

 

I'd like to use an ST-LINK/V2 but I don't see a pin labeled SWIM or Data. The mode I will use is 001. The documentation is not very clear on which is SWIM if I had to guess it should be RxD. Should it be pin 3 or pin 11 or some other pin.

 

Don't forget to wire yourself a SWD footprint of some sort.

 

Already done
Just trying to figure out how to connect the ST-LINK/V2