On Tue, Apr 17, 2012 at 10:44 PM, Sean Breheny wrote: > The behavior you describe may be possible if the commutation sequence > is wrong (e.g., if you have phases swapped on the motor). There are a > number of possible relationships between hall sensor outputs and > appropriate phase drive. Some combinations will not run at all. Some > will run with a different back-EMF constant. Some will run but only if > you give the motor a push to start and then they will have very little > torque. It may be that your commutation sequence is offset by 60 > degrees in one direction so that, for one direction of motion you are > 60 degrees off but for the other direction you are 120 degrees off. > > Sean > > Hmmmm... Possible I suppose. So I guess my next question is, How would one go about creating the hall table? My procedure was to excite a winding pair at lowish current (by loading one of my commutation states into OVDCON and setting 10% DC), waiting for the rotor to stabilize and reading out the current hall data. So, P1OVDCON =3D StateLoTable[1]; and the hall sensors read 011. Thus the third position in my sector table is set to one. P1OVDCON =3D StateLoTable[2]; and the hall sensors read 010. Thus the seco= nd position in my sector table is set to two. and so on... -Denny --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .