Got it working. I plugged the LCD connections into my little Saleae logic analyzer and found that I was getting credible signals for E, RS, D4, D5, D6 and D7. After a bit of poking around in the LCD datasheet, it occurred to me that maybe the floating R/W pin was the problem. I went ahead and grounded that pin and everything seems to be working fine now. Anyway, there might be some variation betby peasejay - RAMPS Electronics
I'm having some trouble getting my 20x4 LCD (basically a homemade ultipanel clone) and my RAMPS 1.4 board talking. I am running the latest Marlin firmware. I am not able to get the LCD to display anything other than the "alternating rows of blocks" test pattern. Please see the attached photos for lcd image and connections. I have been using justblair's connection schematic found here: and haveby peasejay - RAMPS Electronics