CNC Base for Blue Pill
To be used with this port of GRBL for STM32F103F8T6: https://github.com/usbcnc/grbl or with Yaroslav's bugfixed and improved version: https://github.com/yaroslavVl/6-AXIS-USBCNC-GRBL .
This board works with either 3d printer drivers or with external drivers using MKS-CD adapter. An adapter could be made so that drivers that use a common 5V instead of a common GND for step/dir/enable (e.g: the aliexpress TB6600 drivers that come in a black aluminum enclosure) could be used as well.