Color LCD Shield Backlight and Voltage Question

I’m relatively new to the arduino world, have a lot to learn, but am having a blast. I have a Seeeduino Stalker with an AT328 and have successfully run a few of the demo sketches and interfaced into one of your danger shields. That’s all well and good, however, I have recently taken the plunge and purchased one of the LCD Shields (Color LCD Shield sku: LCD-09363). Unfortunately, I am having some trouble with getting the demo code to run correctly and believe it is a hardware problem and am hoping you all can help.

I have been successful in getting the demo code to compile and upload this to the board. But that is about the extent of my success. When plugging the board in to the Stalker I get a bluish back-lit screen with nothing displayed. Perhaps, this is a Seeeduino issue but when I measure the voltage on the 6 pin header I do not receive any voltage on the 3.3V line. I believe this is because I am running the system off of the USB port. Can someone describe exactly which pins need to be powered and at what voltage to get the LCD Shield to function properly? Does it need both 5V and 3.3V? If so how do I rig the board to output both or is this a limitation with the Stalker? Any help you can provide would be great.

Cheers,

Brian

While I’m not giving up as of yet, I did some more examination of the existing setup and here is some more information regarding the pinouts on the LCD shield when it is connected to the Seeeduino board. I’m running the code posted by Peter Davenport and have also tried the example code on the website. Again, they both compile but I just get the backlit screen.

Relative to ground the voltage on the pins are as follows:

Reset : 3.3

3.3V : 2.87

5V : 4.87

GND : 0.0

GND : 0.0

Vin : 0.0

0 : 0.0

1 : 0.0

2 : 0.0

3 : 0.0

4 : 2.64

5 : 2.62

ref : 0.0

GND : 0.0

13 : 3.26

12 : 0.0

11 : 3.30

10 : 0.0

9 : 3.30

8 : 3.30

7 : 0.01

6 : 0.01

5 : 3.30

4 : 3.30

3 : 3.30

2 : 0.04

TX : 3.83

RX : 4.05

bhclowers:
While I’m not giving up as of yet, I did some more examination of the existing setup and here is some more information regarding the pinouts on the LCD shield when it is connected to the Seeeduino board. Relative to ground the voltage on the pins are as follows:

Reset : 3.3

3.3V : 2.87

5V : 4.87

This looks like a power supply problem to me. You’re below the minimum shown on the [datasheet for the 3.3 supply.

I suggest feeding 7 to 12 volts from a generous power supply to the Stalker. (In general, relying on a USB port for power is reasonable if all you need to drive is some logic. If you’re driving motion or illumination (except for low-power indicator LEDs), it’s usually a good idea to provide some other power source.)

Good Luck,

Eric ](http://www.seeedstudio.com/depot/datasheet/Seeeduino_Stalker.pdf)

After trying to find a new 9V, I ditched that idea and hooked the board up to an Agilent DC Power supply (set at 9.0V) and looked at the output with and without the LCD Shield attached with the demo code uploaded to the board. I’ve listed the values below and still receive the same result–just a blue screen. Can anyone verify what values I should be reading on the LCD shield across the pins? I should note that the D5 user LED on the Seeeduino Stalker is on during this entire process (not sure if that is supposed to happen). Again, any help would be greatly appreciated. Can someone think of a way to test to see if it is the Seeeduino board or the LCD shield. I also have a danger shield and a button shield for diagnostics.

Pin NO LCD With LCD

Reset 3.3 3.3

3.3V 0 2.81

5V 4.63 4.5

GND 0 0

GND 0 0

Vin 0 0

0 0.04 0

1 0.04 0

2 0.04 0

3 0.04 0

4 2.62 2.60

5 2.63 2.62

ref 0 0

GND 0 0

13 3.26 3.3

12 0.04 0

11 3.3 3.3

10 0.04 0

9 3.3 3.3

8 3.3 3.3

7 0.04 0

6 0.04 0

5 3.3 3.3

4 3.3 3.3

3 3.3 3.3

2 0.04 0

TX 0.04 0

RX 3.3 3.3

Cheers to all those who gave input, I was successful in getting the shield to function. The problem was, as suggested, inadequate power being supplied to the LCD. It needs 3.3V with very little fudge factor built in. It appears as though there is something a little off with my arduino board which supplies too little power to the shield. Anyway, with an auxillary 3.3V power supply the demo code runs as advertised. While I’m not entirely thrilled with what this means (lots of rigging with a secondary supply or a new arduino board), I’m glad it is working. On a related note, is there anyone out there with success using this shield using the USB cable alone for power and if so which arduino board are you running?

Peace.

Ok, this will hopefully be my final post on this issue. This is more for folk who might run into a similar situation in the future. The guys over a Seeedstudio were quite helpful and described that the Seeeduino Stalker by design has the 3.3V pin disconnected. The attached diagram shows which pins to connect to solve this issue. Thanks again for the help and the example code, nice work.

Cheers,

Brian

ps–my little example mod…

//************************************************************************

// Nokia Shield

//************************************************************************

//* Derived from code by James P. Lynch and Mark Sproul.

//*

//*Edit History

//* = Mark Sproul, msproul -at- jove.rutgers.edu

//* = Peter Davenport, electrifiedpete -at- gmail.com

//************************************************************************

//* Apr 2, 2010 I received my Color LCD Shield sku: LCD-09363 from sparkfun.

//* Apr 2, 2010 The code was written for WinAVR, I modified it to compile under Arduino.

//* Aug 7, 2010 Organized code and removed unneccesary elements.

//* Aug 23, 2010 Added LCDSetLine, LCDSetRect, and LCDPutStr.

//************************************************************************

// Included files

#include <string.h>

#include <stdlib.h>

#include <stdio.h>

#include <ctype.h>

#include <avr/io.h>

#include <avr/interrupt.h>

#include <avr/pgmspace.h>

#include “WProgram.h”

#include “HardwareSerial.h”

// External Component Libs

#include “LCD_driver.h”

#include “nokia_tester.h”

//************************************************************************

// Main Code

//************************************************************************

void setup()

{

ioinit(); //Initialize I/O

LCDInit(); //Initialize the LCD

LCDClear(WHITE); // Clear LCD to a solid color

LCDPutStr(“Click a button!”, 0, 4, ORANGE, WHITE); // Write instructions on display

LCDPutStr(“This library”, 32, 4, BLACK, WHITE);

LCDPutStr(“is for world”, 48, 4, BLACK, WHITE);

LCDPutStr(“domination!”, 64, 4, BLACK, WHITE);

LCDPutStr(“and other”, 80, 4, BLACK, WHITE);

LCDPutStr(“fun stuff.”, 96, 4, BLACK, WHITE);

}

//************************************************************************

// Loop

//************************************************************************

void loop()

{

int s1, s2, s3;

s1 = !digitalRead(kSwitch1_PIN);

s2 = !digitalRead(kSwitch2_PIN);

s3 = !digitalRead(kSwitch3_PIN);

if (s1){

LCDClear(BLUE); // Clear LCD to WHITE

LCDPutStr(“Eat at JOE’s”, 10, 10, WHITE, BLUE);

int xVal, yVal, multi;

xVal = 64;

yVal = 64;

multi = 8;

LCDSetRect(xVal, yVal, xVal+2, yVal+2, 1, RED);

for (int j=0; j<=4; j++){

for (int i=0; i <= j*multi; i++){

xVal++;

LCDSetRect(xVal, yVal, xVal+2, yVal+2, 1, RED);

delay(10);

}

for (int i=0; i <= j*multi; i++){

yVal++;

LCDSetRect(xVal, yVal, xVal+2, yVal+2, 1, RED);

delay(10);

}

for (int i=0; i <= j*multi; i++){

xVal–;

LCDSetRect(xVal, yVal, xVal+2, yVal+2, 1, RED);

delay(10);

}

for (int i=0; i <= j*multi; i++){

yVal–;

LCDSetRect(xVal, yVal, xVal+2, yVal+2, 1, RED);

delay(10);

}

}

}

else if (s2){

LCDClear(WHITE); // Clear LCD to WHITE

}

else if (s3){

LCDClear(BLUE); // Clear LCD to WHITE

}

s1 = 0;

s2 = 0;

s3 = 0;

delay(200);

}

I have the exact same problem - blue/black backlit background but no actual pixels draw.

I have the Mega 2560. I am using usb but the power coming from my 5v is 4.85V and my 3.3V is 4.1V.

I am trying to simplify the problem help localize:

So you can compile the headers for Epson or Philips. Ive tried both, but is there any way to tell which i have?

At a minimum this lcd shield only needs 4 control wires - D8,9,11,13 correct? I have eliminated out all else ( the switches and other connections - i still have 3x ground and 5V and 3.3V wired)

I also dont seem to have control over the backlight by changing LCDContrast(x); with 0 to 63 all having the same effect.

Anyone have any ideas?

UPDATE: I used alternate power to the 3.3V line to get it to 3.3V since it was a little high. Still no luck