Much like the Vision 3D printer, the Viki LCD did not come with any instructions or RAMPS firmware. The following are my notes for how I got it to work. Luckily most of the work was already done by others!
RAMPS 1.4 Connectors
AUX-3 (SD Card):
ViKi – RAMPS Pinout
The Panucatt pdf for the Viki LCD has nice descriptions of the pins and their functions.
Mapping the Viki LCD to the RAMPS board
Viki Top plug – RAMPS 1.4:
- 5V – 5V (I2C, +)
- GND – GND (I2C, -)
- SDA – I2C 20 (I2C, 20)
- SCL – I2C 21 (I2C, 21)
- ENC_B -(AUX4, D17) – requires update to pins.h
- ENC_A – (AUX4, D16) – requires update to pins.h
Viki Bottom Plug – RAMPS 1.4:
- CS – (AUX3, D53)
- BTN – (AUX4, D32) – requires update to pins.h
- DI/MOSI – (AUX3, MOSI/D51)
- CLK/SCK – (AUX3, SCK/D52)
- CD – (AUX3, D49)
- DO/MISO – (AUX3, MISO/D50)
The LCD comes will all of the cables broken out into single pins. I found it helpful to combine them into 4 new headers:
- I2C (5V,GND,SDA, SCL)
- AUX3 top (NC, CLK, D0, NC)
- AUX3 bottom (NC, CS, D1, CD)
- AUX4 (ENC_A, ENC_B)
This leave one remaining pin, BTN, which plugs into AUX4 at the end.
After much searching, I found Jim Morris’s comment on the Viki Kickstart page. After following his instructions, everything just worked! Here they are with a little more detail:
- > git clone https://github.com/repetier/Repetier-Firmware.git
- > git pull https://github.com/wolfmanjm/Repetier-Firmware.git feature/add-vikilcd
- Download LiquidTWI from github
- Install the LiquidTWI library using these Arduino instructions
- Modify the Marlin/Configuration.h with the settings from your previous one. Do not copy it over. You need to edit the new one in place. It has additional configuration that is needed. Here is my new Configuration.h file.
- Modify pins.h to set BTN_EN1=16, BTN_EN2=17, and BTN_ENC=32. Or download my pins.h
- Compile and upload the new firmware and you should be good to go.
Printing Without The computer (“hostless printing”)
The RAMPS that ships with the Vision 3D printer should already have 2 key diodes installed (D1 & D2). If it doesn’t, or if you are running into issues, I found this SDRAMPS blog post very helpful.
In my case, both diodes were already installed, but still I couldn’t print without the USB cable. And after triple checking everything, I finally starting probing the RAMPS board and found a disconnect. Somehow I burnt out one of the traces (probably when I accidentally installed my end stops backwards). I soldered in a jumper over the burnt out trace and I was back in business.