The Y-EN and Y-Step pins are routed to the different arduino port than X-EN and X-Step which make impossible to use Y stepper with the GRBL / horus firmware.
horus-fw/cpu_map.h
// Define step pulse output pins. NOTE: All step bit pins must be on the same port.
same for EN bits
There is 3 unused pins on the port B header but this two signals are routed to the port D instead of port B.
The Y-EN and Y-Step pins are routed to the different arduino port than X-EN and X-Step which make impossible to use Y stepper with the GRBL / horus firmware.
horus-fw/cpu_map.h
// Define step pulse output pins. NOTE: All step bit pins must be on the same port.
same for EN bits
There is 3 unused pins on the port B header but this two signals are routed to the port D instead of port B.