Well, last week after a lot of time spend in research i decide to use the CH32V303 microcontroller from the chinese manufacture WCH, mostly because it's price. but after read after read the documentation and start some PCB routing i discovered that CH32V303 has 4 versions [1}, 3 with 16 TouchKey pins and only one with 10:

And for the surprise of no one the version that i initially choose for this project was the one with only 10 touch capable pins, util there everything was "ok" i only had to pick the version with more pins... but checking the price it turns out the CH32V303RBT6 is at least 50% more expansive than CH32V303CBT6 in quantity:

I really wanna this project been cheaper as possible. So i had no other option than start to search for microcontrollers again. So i spend some hours looking for Silver.. than a i found Gold; The CH582M:

The chip not only have 14 touchKeys and USB support, but also have Bluetooth Low Energy module AND are in the same price of the CH32V303, so it is the perfect choice, and maybe it can add a feature that wasn't in my plans; wireless.


Here's the actual drawing: