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gnea / grbl

An open source, embedded, high performance g-code-parser and CNC milling controller written in optimized C that will run on a straight Arduino
https://github.com/gnea/grbl/wiki
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M8 command - which pin, what signal? #882

Open cvhorie opened 4 years ago

cvhorie commented 4 years ago

I am using (or at least moving in that direction) Arduino/GAUPS(a gShield clone)/GRBL/Pascal to move an Olympus camera over a surface. Once in position, I need to tell the camera first to focus then to activate the shutter. Each is achieved by shorting the appropriate camera control wire to GND.

As a novice, it seems that M7 and M8 are the most appropriate commands to use.
I should be grateful to be pointed to the file that specifies the appropriate pins and the signal GRBL sends to them. I can then use relays to short the wires. More generally, it would be useful to have this information for other commands.

Any advice gratefully received. Thank you.

langwadt commented 4 years ago

https://github.com/gnea/grbl/blob/master/grbl/cpu_map.h

cvhorie commented 4 years ago

Thank you. I would have struggled to find the file, if I had know it existed. One remaining piece of useful information is: If I call M8, what happens to the signal on Analogue pin 4? Is it an analogue 0~5 V, or a digital 0>5 V?

langwadt commented 4 years ago

it is a digital on/off 0/5V

https://github.com/gnea/grbl/blob/master/grbl/coolant_control.c

cvhorie commented 4 years ago

Thank you. I guessed the wrong way round. At my stage of ignorance, I need a cook book - but I do like to know where the ingredients come fom. You referenced Dr Jeon's file (and what a lot of work he has put into GRBL). It does not mention the physical output you kindly gave. Is there a (simple?) description of the electrical outputs which are generated by the programmed commands, or is this board dependent, or too interdependent?