This page describes the ongoing saga of retrofitting a commercial Panormama Head(in this case a Nodal Ninja 3) with stepper motor controlled positioning for automated large panorama captures.
At present all I have is a first draft of some code for a stepper motor controller controller, which takes serial input and outputs Step, Direction and Power pins for a stepper board like the PICList Linear Stepper Controller
The code compiles under SDCC for the PIC 16F628, and probably the 16F628A, I just don't have one. For the 628 I use an external oscillator since the internal RC clock isn't accurate enough for serial. The 628A may solve this. Serial input/output is on the standard 628 USART pins at 9600-8-n-1. Commands are of the form: motor letter direction number of steps terminator. Motors are x and y, y is not yet implemented, direction is + -, and number of steps is decimal up to 65535, the terminator is comma(,) linefeed(10) or carriage return(13). So, sending x+10, will step motor x 10 steps in the positive direction. Direction can also be a b c or d to change various parameters in the code, these are not saved across reset, this is mostly for testing and then once you find good values then hard code them and recompile. On motor start the code sends 'xgo' or 'ygo' and on end of motion sends 'xok' or 'yok'.