Hi Karl et al,
There are multiple ways to skin the multiple focuser cat
The current SharpSky LED outputs are not suitable for driving a motor as the LEDs are driven directly from the PIC which can easily source 20mA per I/O. The motor is driven from the Darlington driver which is good for about 500mA continuous per output and is so good for motors with windings in excess of around 30ohms.
The good thing about PIC projects is the hardware is relatively simple. However, the detail then sits in the software both embedded code and driver code. Adding an extra motor ripples all the way up the software chain including the client. The standard ASCOM driver & API is only dimensioned for control of one focuser. There are two options to get around this. We could use a server to handle multiple focuser instances. Or we could generate two separate drivers, say main & guide scope . These two drivers look like two independent focusers to the client. We could then multiplex the two bidirectional command streams over one USB connection to a single piece of dual motor hardware but that means everyone has to pay for a two motor solution when the vast majority only want one. So the other option is to have a generic single motor controller that the user can configure as main or guide scope. So in the driver you tell the focuser hardware whether it is to be a main or guide controller and it is then configured with a unique USB identifier so the two controller can be addressed independently - I have tested this and it works well.
Crumbs, sorry about that got all carried away .....
Cheers,
Dave