Hi there
I have been using the K107 in my Picaxe projects and I think they are great. I have been dabbling using a Fez Domino, and trying to send a string to the K107 LCD (whcih worked ok with the picaxe. I can get some characters, but I think the code I am using sends Bytes to the K107 (not sure how top send anything else in C#). I am trying to use the commands (K107 eg ?a) but i cannot convert these to bytes (not sure, a byte should be a int value???). I’ll send code that I have hacked (using UART in C#), can you help?

I can take a look for you. I started out with the PICAXE and have used a combination of PICAXE and LCD in several projects. Send me a copy or post it as a comment and I will take a look.

Hi Pixel

I will cut and paste the code in here. I have couple of questions… Why can I only find code that sends byte data to the serial port (I am used to SEROUT on a picaxe, so easy) and I would imagine that the commands for the LCD in this code are all byte data, but they should be string data with the K107 commands starting with “?”. So frustrating to not know enough about it. I hope you can help, and I’m up for “stating the obvious”

Cheers

Here is the code that I like the most. (there are heaps of examples but this is pretty tight)
(source code or class)
using System;
using System.IO.Ports;
using System.Text;
using System.Threading;
using GHIElectronics.NETMF.FEZ;

namespace LCD
{
public class SerialLCD
{
const byte DISP_ON = 0xC; //Turn visible LCD on
const byte CLR_DISP = 0×01; //Clear display
const byte CUR_HOME = 5; //Move cursor home and clear screen memory
const byte SET_CURSOR = 0×80; //SET_CURSOR + X : Sets cursor position to X
const byte Move_CURSOR_LEFT = 0×10;

private SerialPort UART = new SerialPort(“COM1″, 9600);

public SerialLCD()
{
UART.Open();

}

public void Print(string s)
{
byte[] buffer = Encoding.UTF8.GetBytes(s);
UART.Write(buffer, 0, buffer.Length);
}

public void ClearScreen()
{
SendCommand(CLR_DISP);
}

public void CursorHome()
{
SendCommand(CUR_HOME);
}

public void SetCursor(byte row, byte col)
{
SendCommand((byte)(SET_CURSOR | row << 6 | col));
}

public void MoveLeft()
{
SendCommand(Move_CURSOR_LEFT);
}

private void SendCommand(byte cmd)
{
SendByte(0xFE);
SendByte(cmd);
}

private void SendByte(byte cmd)
{
byte[] buffer = new byte[1] { cmd };
UART.Write(buffer, 0, buffer.Length);
}
}
}

——————————–
execution code

using System;
using System.IO.Ports;
using System.Text;
using System.Threading;
using GHIElectronics.NETMF.FEZ;
using LCD;

namespace FEZ_Domino_Application1
{
public class Program
{
public static void Main()
{
SerialLCD lcd = new SerialLCD();

lcd.ClearScreen();
lcd.Print("FEZ is great");
lcd.SetCursor(1, 0);
lcd.Print("Hello"); // prints on the second row
}

}
}

———————————————————–

I don’t see anything particularly wrong in the code snippet. But there are 2 things I noticed that might be causing the problem.

1) Make sure your K107 is actually set to work at 9600 baud. I think the newer versions ship with a higher default baud rate (You can check by just using your PICAXE setup to test the LCD).

2) I am no expert at C# but I think you need to use a different function in place of Encoding.UTF8.GetBytes(s). The UTF-8 translation is probably messing up the actual bytes being sent across the serial line.

Hope that helps with your problem.
Pixel

Hey, got it working (almost) baud rate was spot on, and I inverted (through jumper on k107) for rs 232 (duh) however, not sure how the code sends commands the the LCD. I am used to sending the commands as strings (ie ?A) as a newbie to C#, obviously the commands are sent as bytes, am I not getting something here. The LCD (4×20) is writing the first line “FEZ is great” on the first line , but the H in “Hello” is also on the first line with “ello” on line 3. I get that the code is set up for a 2X16 LCD but how????? thanks so much for the guidance so far

The LCD geometry is definitely your problem. LCD’s use addresses to reference each character position on the display but the addresses from line to line are not sequential. For example on a 4×16 LCD the addresses work like this:

Address
0×00-0×15 – Line 1
0×32-0×47 – Line 2
0×16-0×31 – Line 3
0×48-0×63 – Line 4

You will notice that when you reach the end of the line and keep printing characters they start appearing on line 3 NOT line 2 because of how the address space is organized. This also causes all kinds of problems when the K107 thinks it is using a different sized display than it actually is because all the positioning the K107 does is based on these address ranges.

Now to actually solve the problem you will need to tell the K107 board that it is driving a 4×20 so that it knows how to ‘chop up’ the address space. For the K107 this is super simple and only needs to be configured once when you plug in a new LCD with a different geometry. It remembers the geometry between disconnects.

To set the geometry for your display you need to send the “?G” command (which is explained above) with the number of lines followed by the width of the display (in characters). So for a 4×20 display you would send the string “?G420″ at which point you should be all set.

Hopefully that should fix things.