Stepping motor driver on the input pulse of the current size requirements, I directly with the microcontroller pin connected to the drive pulse input, but the microcontroller pin current is very small, very small
SCM P1 mouth to absorb current can reach 15mA, but I suggest you use current limiting resistors to limit the current within 5mA.
Each production is not the same, the general situation of 5 to 15mA, I usually use 7.5mA or so. SCM direct drive is also OK, but you must be connected to low level effective.
The current of the control signal is certainly not large except for the ability to increase the signal's anti-interference capability
