using shiftLCD library

I am using a 74hc595 shift register with an Arudino Uno so I can save pins using the 20x4 LCD. So I downloaded the shiftLCD library that I found here: http://cjparish.blogspot.com/2010/01/controlling-lcd-display-with-shift.html I noticed on that site, it tells you to ground the R/W pin of the LCD. But on this page: http://www.hacktronics.com/tutorials/arduino-character-lcd-tutorial.html It says the R/W pin goes to pin 11 on the Arduino. Which one is right?

The reason I ask is because I am displaying a menu on the LCD with two buttons that control whether the cursor goes up or down. Whenever I put my fingers near the buttons, the cursor starts moving on its own. I figure this is because I am grounded and therefore grounding the switch. However when I used the exact same code without using a shift register and using LiquidCrystal.h everything went how it was supposed to.

Any suggestions?

Thanks a lot!

How are the buttons wired?

Good call, I wired them wrong. Dummy points for me. I'm still curious about the difference in R/W pins though. It seems right there you could save a pin on the Arduino using the LCD if you just wire it to ground. Maybe that won't work without the shift register though. Thanks johnwasser.

I am using a 74hc595 shift register with an Arudino Uno so I can save pins using the 20x4 LCD. So I downloaded the shiftLCD library that I found here: http://cjparish.blogspot.com/2010/01/controlling-lcd-display-with-shift.html I noticed on that site, it tells you to ground the R/W pin of the LCD. But on this page: http://www.hacktronics.com/tutorials/arduino-character-lcd-tutorial.html It says the R/W pin goes to pin 11 on the Arduino. Which one is right?

They are both right. Implementing the R/W line gives you the ability to read data from the LCD controller but this ability is rarely needed. The shiftLCD library apparently does not read from the LCD controller so they tell you to connect R/W to GND thus implementing writing. You must ground this pin, it is not an option. The LiquidCrystal library does give you the option to connect this wire and have the program ground the connection for you. The library does not (presently) make any provisions for actually using this pin so there really is no advantage to connecting it and in doing so you use up an I/O line on your Arduino. For some unknown reason the hacktronics tutorial does have you connect the wire but you will get exactly the same results if you do not connect R/W to pin 11 of the Arduino and instead connect R/W to GND.

Don