Laser pin for curent firmware and mini rambo on lowrider2

@Ryan and company. I would like to use my diode laser on my LR2 while I am in the process of building the LR3. Does anyone know what ttl pin I should use on my mini Rambo and give me easy instruction for editing the current firmware if needed?

Thanks as always,
Dan

The pins seem kinda scarce. I used a zmax pin but your probably using that one. Here is a thread I found helpful. Laser, Marlin 2.09.2 mini Rambo 1.3a
Someone with more knowledge is bound to come along.

Zmax might work. That should be an unused pin on the mini. Thanks!