This block diagram is DRV8711, a Stepper Motor Pre-Amplifier from TI. This cost around 5.- USD as samples, so I am not sure I want to bother about it. But, I find it very interesting because it has an easy step/pwm interface as well as a more complex SPI. It adds features like stall detect in logic, current sensors on both phases, BEMF etc.
I am not sure if I want to use these advanced pre-amplifiers or use more complex code. Using discrete half-bridges also enables other options to use them separate. Modern MCU’s are also so powerfully that its not rocket sciense to do the same in software + a bit of electronics. But, well we will see – I will keep an eye on the price and study this one a bit.
Driving a stepper is a rather straight forward + using software you can apply different algorithms. If you use an integrated pre-amplifier like this your locked to the logic implemented by the vendor. It’s ups and downs with everything.