Originally shared by Sebastian Szafran Today I tried PCB probing and thought it will

Originally shared by Sebastian Szafran

Today I tried PCB probing and thought it will go smooth. But I was wrong. Homing and limit switches work perfectly every time. Touch plate zero’ing and test probing goes well, too. But when I start the probing process after few correct probes tool goes down to Z=0.5 (probe start height) and then it is immediately saving probed location with Z=0.5 and move to another probe location. This happens repeatedly until again it starts normal probing (for some time) and then again Z=0.5 -> see pictures.

@Alden_Hart @Riley_Porter_ril3y Might you have an idea what else to check?

I wonder if this is a g2 bug or inconsistency from the v8

More I think of this problem, I am convinced this is still related to noise. Tomorrow I will try to put a capacitor between D18 (probe) and GND directly on the Due, so it is as close as possible and maybe lower pull-up value.

Is it possible to disable G2 on-board stepper motors drivers and use external motor drivers instead while still under control of TinyG2?
The potential problem I see is that all connectors for logic and motors are very close on the board and motor wires are likely to create spikes. Just another idea to eliminate the problem.

And how it works on native TinyG, as many people are using it with success? Should I consider TinyG board and stop playing with Due+gShield tandem?

gShield works great with grbl on Uno, but in that case probing uses A5 analog pin, while on Due it is D18 digital pin.

@sszafran External drivers? Yes, I bet more folks are doing that than using Gshield. Try a Google search on tinyG2 External Drivers.

I would sort of agree that all these motor wires jammed together around DUE and GShield are tough to manage.

I would get your input impedance down real low on D18 with cutoff freq still 150Hz or below, see if that helps.

If production is your requirement, tinyG will be more mature for a long time. If more axes and bleeding edge are you goal, G2 is the place to be.

Today I did more tests with noise eliminated. I used my ‘running in the air’ Nema 17 kit, wires isolated, low motors current, RC filters.

The probing works wrong based on my experience. It begins correct and suddenly start the bad-probes at Z-probe-max height with no respect to the probe pin logic level. This is sometimes 0V and sometimes 3.3V all in the same probing cycle. No really a rule for logic HIGH or LOW causing the issue.

I tested also with firmware 87.01 available via Chilipeppr Programmer Widget and for that firmware version to work I change the probe wiring to pull-down resistor circuit. When probe switch is opened it is 0V, and when it closes it goes 3.3V. That looks like version 87.01 is compiled with probe set ACTIVE_HIGH by default. The same situation happened: after few correct probes I got some bad, good again and bad and good… with probe pin logic level HIGH or LOW.

I also found that rarely after machine and the TinyG2 first power-on Touch Plate ‘reacts’ two times on the first usage. It goes double high (2mm once, stops for a short time and go high by another 2mm again).

What do I need to start debugging, Atmel ICE Debugger?