Nema 23 not working

I am using the A4988 Board. I have hooked a Nema 23 Bi-polor motor that is 1.8 degrees/step and rated at 1.5 Amps /Phase.

My logical power supply is set at 4.2 volts, well within the limits of [3.3v - 5.5v]. I created a Voltagedoubler circuit to get around 8v for the VMot Pin. When I take the volt meter to read to VMOT pin I am getting around 0.914 volts. Obvious not enough to drive the motor.

Secondly, the power supply is showing 0.00Amps at 4.2 logical voltage ??

What am I doing wrong ??

Thank you in advance

It is extremely unlikely that your mysterious voltage doubler circuit will work to power a stepper. You need a Vmot power supply capable of providing a couple of Amperes steady state, 8 to 24V (the higher the voltage, the faster the motor will step).

You need to carefully follow the directions to set the current limit to 1 Amp/winding or less. Add a capacitor across Vmot as suggested on the driver page.