My Fork: https://github.com/not404/Repetier-Firmware
Pull Request (Accepted): https://github.com/repetier/Repetier-Firmware/pull/397
I’m not sure why this hasn’t been done yet, but here you go, World. My fork of Repetier Firmware, complete with PrintrBoard Rev. F digital trimpot support. Additional M-Codes in support of the digital trimpot are implemented (using PrintrBot’s Rev. F fork of Marlin as a reference guide):
- M907 – Set digital Trimpot using axis codes
Accepts S[0..100] to set ALL channel outputs to a percentage of maximum-allowed value. Also accepts X, Y, Z, and E values from 0 through 100 to set each axis to a percentage of maximum-allowed value. note that S must be an integer; whereas X, Y, Z, and E may accept float (decimal) values.
- M908 – Set Digital Trimpot Manually
Requires P[0-4] to specify Stepper Channel (X, Y, Z, and E respectively), and S[0..3520] to set the DAC channel value. 3520 corresponds to 1.76 Volts out on the DAC Channel — which itself corresponds to a maximum of 2.0 Amps of output on the Stepper Driver. (See the datasheets for an explanation if you must).
- M909 – Display MCP4728 Values
Displays the EEPROM-Saved Values and the Current Runtime Values for X, Y, Z, and Extruder.
- M910 – Commit to EEPROM
Saves the “Runtime Values” to the digital pot’s EEPROM. Upon subsequent starts, the EEPROM is read back by Repetier to get the startup values. Note also: If you use M910 to save to EEPROM, and replace Repetier Firmware with something else (that may not have support for the MCP4728 trimpot), the values in EEPROM will continue to be used by the MCP4728 on startup — you just lose Repetier Firmware’s ability to change or refine the digital trimpot if you go this route.
With this firmware in place, there’s no reason to waste your time and energy on earlier PrintrBoard revisions — unless you managed to pick one up at a great price, of course.
For $99 and change via PrintrBot’s website, the PrintrBoard Rev. F is a decent piece of hardware for small hobby-grade 3D Printers, and with the digital trimpot onboard, there’s less chance of amateur mistakes with tuning the trimpots and burning out the stepper driver chips.
Drop me a private message if you happen to need additional (paid professional) help in building Repetier Firmware for your board or device.