Application Circuit to Control 2-Stepper Motors Using PCA9673 FM + Quasi Bi-Directional GPIO

Application Circuit for 2-Stepper Motors using PCA9673 GPIO Expander. The PCA9673 Fast-mode Plus quasi-bidirectional GPIO outputs are CMOS compatible. This allows the use of power driver ICs that have the capability to accept CMOS compatible outputs. As an example, ULN2803A has 8 high-voltage, high-current Darlington arrays with open-collector outputs and integral clamp diodes (flywheel diodes) to deal with inductive loads. Coil voltages can be as high as 48V