Connecting an Arduino Mini-pro to a LCD display

Using Arduino Project Guidance
1

Hi,

I'm trying to connect an Arduino Mini-pro (5v version) to this LCD display....Basic 16x2 Character LCD - Black on Green 5V - LCD-00255 - SparkFun Electronics.

I've had no trouble connecting this LCD to a Uno or a Mega in previous projects, so I though it should be just as easy for a Mini-pro.

I've been working from the example shown here....

The only change I've made from the uno/mega versions are the pin numbers, these are the pins I've used....
LCD RS pin to digital pin 4
LCD Enable pin to digital pin 5
LCD D4 pin to digital pin 6
LCD D5 pin to digital pin 7
LCD D6 pin to digital pin 8
LCD D7 pin to digital pin 9
LCD R/W pin to ground.

so I intialise the LCD with the command LiquidCrystal lcd(4, 5, 6, 7, 8, 9);

My sketch is based on the tutorial above, but has been changed to display a slowly incrementing number rather than just 'hello world'

The sketch will successfully display the number to the serial monitor, but not to the LCD. I guess this proves the mini-pro is working ok. The sketch will also work fine with the Uno/mega versions. I've continuity tested my (homemade) shield so I'm reasonably confident that the screen is wired as intended. The LCD itself is mounted on header pins, so I can remove it an put it in another shield where it works just fine.

Any suggestions for further test/changes I can make? My current best-guess is that either the pro mini is simply not compatible with the LCD screen, or some of the individual pins I've used aren't suitable.

Suggestions appreciated!

2

What about the LCD contrast? Do you have anything connected there as without it the display will probably not show up though its working.

3

Panic over! - It was a nearly microscopic short on the shield.

Bugger - should have spent more time testing the board and less time writing the post!

cheers

4

Glad you got the problem sorted. Shorts and open circuits are a PITA for home builders.

5

If I had a nickel for every time I've troubleshot a hardware problem by looking in the software...