With stepping it seems to be oki with comparator protection, so you can use the Vref inputs as you want. Improving L297 based Unipolar stepper driver, L297 stepper motor controller clock signal question, L297 + L298 circuit not working, Trouble with L297 pins, Switching power to Stepper Motor Drive using relay and arduino. Software is used in this case to protect the chip and the motor if you apply a heavy load, or the motor is stopped by external forces. For short circuit protection, you should use hardware. If high current is higher than normal current for so long time, I'll cut down the chip. I use software to detect the high current. That why I use SenseA, and SenseB connect directly to microcontroller.

It receives basic TTL (Transistor Transistor Logic) logic levels and is able to operate the different loads such as DC motors, stepper motors, relays etc. However, I don't use it in my driver, because as I said, a high current could be created at the beginning (especially with DC motors), so if you chop down the chip, you cannot control the driver anylonger. Stepper Motor Using L297 And L298 Ic Download L298 Datasheet L 298 is a dual full bridge driver that has a capability to bear high voltage as well as high current. However, a internal comparator of L297 can be used, and you can apply the max voltage to chopper the driver, if the current is going too high. SenseA, and SenseB are connected to Vref of uC, that is why I say Vref is the output from driver chip. Oh, sorry, I said about the Vref on uC, that I use to control L298.

Stepper motor driver ic l297 l298