My MPCNC has the V1E touch plate. it’s been working fine, but all of a sudden, it just stopped triggering when it’s closed the circuit. I unplugged it from the board and tested with a multimeter - I have continuity from the touchplate to the pin in the plug and from the magnet in the copper clamp to its pin as well.
I replugged it and the issue persisted - when the magnet in the copper clamp (wired to ground) is on the bit of the router, and it touches the touch plate (wired to signal), the light on the SKR Pro which usually lights up when the touchplate is triggered does not light up. Z homing fails since it’s not ever seeing the circuit as completed.
I’ve unplugged/replugged, power cycled, even resoldered the touch plate to the signal wire, but the situation persists. Anyone know anything I can try?
I put back the last tool I used, which worked fine with the touch plate, and the issue persisted. I don’t even get the light on the board when I touch the clamp to the touch plate directly.
I’m not sure if you meant for me to put the jumper here, but doing so did not change the state of the board - the Z0 LED still does not light up and the Z homing still fails to trigger.
That’s acting like a blown GPIO. If you temporarily hook up the touch plate to an endstop location and then touch the plate to the probe ground, does it then light up?
If I move the touch plate plug from E1 to Y (immediately to the left of where it’s always been) and move Y to E1, both the touchplate and endstop trigger normally without incident. If I return Y to its original location and move the touchplate to E2, and touch the touchplate with the copper clamp, E2 seems to function without issue. Granted, it’s operating as NC - the light on the SKR stays on and goes off when the touchplate is triggered.
OK this is funky and I’m not sure how to troubleshoot it when you swap them and they both work, then swap back and only one works. I suspect it’s some kind of return/referencing thing but need to chew on that a bit more.
Maybe some other forum members have some suggestions.
Give me a little bit to think, and see if other jump in.
When you have the swapped setup, if you toggle the Y1 endstop by hand, does M119 show a change in the Z_min?
There’s a small chance that this is a manifestation of a problem that SKRs get where they have a wacky LED pull up circuit. These can sometimes work for a while then get flaky.
The last possible steps to troubleshoot this would be to try making a pigtail to modify the pullup circuit, or moving the probe pin to another location on the board and rebuilding the firmware for that different GPIO.
It does look to me like a board issue, possibly the pigtail can work around it and possibly a firmware change to move to a different GPIO are the last options I see.
No change in z_min when the Y1 endstop is triggered, but when Y1 is triggered, it shows Y_MIN as triggered. Which is weird because Y1 is still in the Z- plug.
The E2 plug is open, i could just move the touchplate to that and rebuild the firmware to use that. At least that way I don’t have to physically risk the board by soldering a pigtail. Is there maybe a guide for flashing the firmware somewhere?
You’ll want to get platformio installed on your computer and then grab the latest V1 firmware for your SKR/MPCNC. There’s a link to github on the V1 docs page. From there, we’d want to change the IO pin defennition and then rebuild.
The good news is that I’m slightly familiar with futzing around in 3D printer configs from a year or two back, so Platformio and changing configs is not new to me.
The bad news: I can’t for the life of me find the IO pin definition and I’m not certain where I’d go to get it to use E2 for the endstop instead of Z-.
The closest thing I could think of and google up was to find what defines PG8 as the Z- endstop. Marlin\Marlin\src\pins\stm32f4\pins_BTT_SKR_PRO_common.h has this snippet:
In order to get the touch plate on the E2 plug, do I just change #define Z_MIN_PIN from PG8 // Z- to PG5 // E2 or are there other configs that need changing?
I was able to change the config and compile - the Platformio docs on the MPCNC side are a bit out of date, I had to go into the Platformio extension and open a project from the Marlin subfolder within the V1 firmware before it made the build option visible.
I copied the compiled elf file to a microSD, put it in the microSD slot on the SKR, put the touchplate in the E2 plug, and booted. Now it lights the E2 light whenever the touchplate is open and the light goes off when it is closed.
It still doesn’t trigger a Z stop - if I move Z up a few cm, then run Home Z, then touch the touchplate to the clamp, the light goes off but the tool keeps moving.
M119 shows all endstops as open when I run it either with or without the touchplate triggered.
