Serial LCD (basic) problem

Other Hardware Displays
1

Hello Everybody,

First of all I'm happy to be a new member of that forum.

I've a very basic problem with an LCD Serial device.

I would like to use an old AXE033 device (serial 16x2 LCD), see doc join)

All scketchs doesn't work, I only get some strange characters on screen.

Here one of my scketch

void setup() {

Serial3.begin(2400,SERIAL_8N1);
}
void loop() {

Serial3.print(254); Serial3.print(128); //LCD position

/Serial3.print(" Hello "); // show "Hello"

delay(200);

}

Do you have any idea?

Thanks for your help.

AXE033.pdf (212 KB)

2

Do you have any idea?

Yes. Move all of your code into setup() and leave loop() empty (nothing between the { } braces).

Don

3

Yes. Move all of your code into setup() and leave loop() empty (nothing between the { } braces).

Don
[/quote]

Hi thank you, same result, only strange characters.

kind regards;

4

It looks like you are using the PICAXE 'Test program' on page 8 of the manual in your link as the basis for your program. Why did you leave out the first step?

init:pause 500 ‘ wait for display to initialise
main:serout 7,N2400,(254,128) ‘ move to start of first line
serout 7,N2400,(“Hello!123”) ‘ output text
end

Don

5

Hi,
This thread was really helpful in solving the same problem for me, but there's a few key bits of info missing. So here goes..

  • I used an Arduino Mega 2560 and AXE033 16x2 Serial LCD
  • I used the "TX 18" pin on the Arduino Mega which is 'Serial1' (Serial 1,2,3 aren't available on all Ardunio boards)
  • You need an inverter on the Serial TX line between the Arduino and LCD (I used a 74LS04N that I had on hand) - The LCD is 2400, N, 8, 1 so the correct serial setup on the Arduino is 'Serial1.begin(2400,SERIAL_8N1);' which is also the default.
  • I put in a jumper bridging the RST connections on the LCD - not sure if it was necessary in the end
  • The LCD does not have any input buffering. This means the 1st char will get through and most of the rest will be rubbish. Solve this by sending a byte and then a 5msec+ delay. It means that you cant use the serial print commands to send a text string and have to use the serial write command to send it and individual bytes. This includes sending control commands. I didn't try the ability of the LCD to use stored strings. That may make a few things easier.

eg.

// For the AXE033 Serial LCD (16x2) you have to use an inverter (eg. 74LS04N) between the Arduino output and the LCD serial input pin.

const int comm_delay = 5; // the AXE033 Serial LCD doesn't have input buffering and needs a delay between bytes ... 5 msec or higher
int i;
String stringOne = "Hello";
int stringlength;

void setup() {
Serial1.begin(2400,SERIAL_8N1);
delay(500);

// clear screen
Serial1.write(254);
delay(comm_delay); // the AXE033 Serial LCD doesn't have input buffering and needs a delay between bytes
Serial1.write(1);
delay(comm_delay);
stringOne = "Hello There";
}

void loop() {

// move to 1st line
Serial1.write(254);
delay(comm_delay);
Serial1.write(128);
delay(comm_delay);

stringlength = stringOne.length();
for (int i=0; i <= stringlength-1; i++){
Serial1.write(stringOne.charAt(i));
delay(comm_delay);
}
}