I'm facing with very odd problem (for me at least). I've fought with this half of the day to day and gave up ending with no more ideas what to do.
My board (original Smoothieboard v.1) has worked since almost two years without the problem. Today I had to change soft limit parameter and put into the slot a SD card with not finished saving probably (withoutnot safe remove). And my switch modules has stopped to work. And they still don't work after loading config copy (I had it saved).
Stopped to work means their out ports (P2.4-2.5) are like burnt, always in the low state and ignoring their config data. Don't react for input pin, don't react for control gcodes.
- change initial behaviour from true to false - port always in low
- redirected output port 2.5 to another - new port doesn't work, old port stil in low state
- reflash the firmware
- format SD and rewrite the config from the begining.
At the same time, other parameters of config work properly.
So it does not look like slot or card issue. If I change homing directon - it works. The same steps per mm. Everything but switch modules.
Finally I thought the ports are burnt, no reason why as nothing electrically has happened, but everything's possible... But, if I press ISP switch and turn on the power - these damned ports are high! Then after the restart they again go to low state. So they work properly.
No idea what to do any more. Any advise???