I’ve already used this pin to connect my laser, and you can read more here. And for this we need unmodified/unboosted PWM/TTL signal for laser. This could have been changed, because recently there are cheap, Chinese devices with exchangeable spindle and laser modules.

I have Woodpecker board 0.9 (like the one used to draw schematic on the right picture), but it looks like newer one (or just different) since mine instead of one “Z endstop (Zen)” connection has connected there ping 15 of ATMega chipset (this is Arduino pin 11). The only thing that remained was to find Arduino 11 pin (PB3), and this happens to be pin used to PWM spindle motor. But despite this, in some posts I saw people soldering connection directly to chipset – this should be last resort, and there are usually better ways. As you can see, on it, almost all connection are available on bottom pin row. Really helpfull here was drawing (on the right) already made by rseijo on GRBL git issue forum. But in exchange we gain more responsive and easier to connect to bootloader, and more memory in ATmega328P. You need AVR programmer (or another Arduino board) and you have prepare some cabling, perhaps do a tiny soldering. You have to start upload just right, after powering the board with USB – otherwise it won’t connect to bootloader (unless this was in my case).īurning new bootloader is bit more tricky. Changing GRBL is quite easy – just use avrdude and upload hex grbl file. But it uses ancient GRBL 0,8 or 0,9, and has old Arduino bootloder. It has three sockets for pololu motor drivers, spindle and laser connection etc. Woodpecker is quite old (but still sold), Chinese board for CNC machines.

Just needed to find proper way to connect to the board. Anyway since I anyway wanted to upload newer bootloader no harm done. Interesting thing – firmware was still working ok. I’ve downloaded binary firmware (to back it up) with chosen ATmega2560 instead of ATmega328P – since it has more memory, dump was too big to fit later in 328p and when I wanted to restore it, I’ve overwritten bootloader. Not so long ago I’ve managed to corrupt my bootloader in woodpecker board by silly mistake.

Woodpecker 3.2 grbl probe