Topic: Davinci 1.0 with BTT SKR 2.0 board. Optical endstops working
Hi,
I acquired a Davinci 1.0 with a busted controller and have swapped it out with a BigTreeTech SKR 2.0 board running Marlin firmware. I got much of the hardware working (e.g., optical endstops, extruder optical encoder, etc.) and thought I'd share what I learned in case it helps anyone. I listed the high-level work below - I can provide more details / pics if there's interest.
Hardware modifications
BTT's github page for the SKR-2, which has schematics and pinouts, was very helpful.
The main work was rewiring, switching connectors from Davinci's JST-PH to the JST-XH ones that the SKR-2 expects. Plus figuring out which wires to plug in where.
The davinci board had a current-limiting resistor in series with one of the wires to each of the optical endstops (to limit current through the LED). The SKR-2 has no such resistor, so I added a 270-ohm resistor in series with those wires.
That's it! The rest worked by plugging into the right spot on the SKR-2, including: extruder optical encoder, filament detector, thermistor, fan and heater, bed thermistor and heater, case light, and of course the stepper motors.
Along the way, I believe I learned what each of the 7 wires going to the board in the extruder does.
Firmware
I put my modifications to Marlin in a Github branch of my fork on Marlin. I believe I've calibrated the x,y,z and extruder steppers to within 1%. I tried calibrating the bed and extruder thermistors using a separate type-k thermocouple and am probably only within 5% or 10% for those (because I measured from a different spot than exactly where the thermistors are).
It looks like Marlin does not support having both an extruder encoder (to detect jams by noticing the idler wheel isn't moving though the stepper is) and a filament sensor (to detect filament at all) - you have to pick one or the other. I selected to make Marlin use the encoder since that catches more problem scenarios than the filament sensor.
Todo
I didn't hook up the bed level-detection sensors. A piece of paper seemed to work fine.
I also haven't actually printed anything yet, so take this post with a grain of salt. I'm having trouble getting the hot-end to extrude consistently. I think I may have some bad heat-creep and/or missing ptfe or something. I'm going to take apart the hotend and hopefully figure out what's wrong.