hi, can this image use traight to gpio too, rp4b board and i made 3,3V to 5V output level converter board use traight gpio output to stepper motor drivers DM556,
and same i build optocouplr board all input opto to gpio can use safety all gpo, not used BOB card or other board, i made diy own in/out gpio to 5V convert board, hope image can use straight all step/dir, enable, signal out to gpio pin. its easy use level converter module can convert 3,3 rpi output to 5V input by stepper driver controller etc, DM556.
same i think can easy use optocoupler module all input gpio pins. 5-24V in to opto and then 3,3V safety to in rpi gpio.