Double Stepping???

Folks:

I'm in the debug phase of setting my Sherline Mill as a CNC unit. I'm using
the Camtronics amp driver and TurboCNC to drive it.

I'm noticing that, after I power up the driver board and load TurboCNC, I
can give the command: G00 X1 Y1 Z1 and all three axes move one inch in the
proper directions. Then, if I issue the command G00 X-1 Y-1 Z-1, all three
axes move TWO inches in the proper directions.

From then on, directing the motor to move 1 inch in either direction causes
a movement of two inches.

My first thought was that the stepper motors were full stepping instead of
half stepping, but that doesn't explain the fact that the first motion is
correct. Later, I'll be connecting a scope to the full/half step pin of the
L297 to try to monitor what's going on there. Does anyone have any
experience with this combination of driver software? If so, I'd appreciate
any ideas of what is happening or where else to start looking.

Thanks for your assistance,

-- Jerry Jankura
Strongsville, Ohio
So many toys, So little time....