> A 2803 has bleeder diodes to the Vcc, which is the only function of the
Vcc
> pin. Don't forget to connect it, otherwise things will work normally but
> only for a short time. The bleeder diodes protect the 2803, the circuit
> driving the 2803 won't notice any spikes.

The motor windings should not be running from VCC, and returning those
diodes to VCC will be potentially a very interesting experience. You should
return them to the motor supply voltage.

Returned to VCC, all the spikes from motor coil switching are dumped onto
your VCC line. Further, if your motor voltage is more than a diode drop
higher than VCC, you will be running current from the motor supply onto your
VCC, which has serious consequences for any regulation you might be trying
to achieve on VCC.